阅读说明：本技术 无线电池充电期间的带内通信 (In-band communication during wireless battery charging ) 是由 毛小林 吴宝善 杨松楠 未海洪 周维 于 2019-04-26 设计创作，主要内容包括：本文描述了一种具有无线电能接收器的装置，所述无线电能接收器包括用于无线接收电能以及进行无线通信的接收线圈。所述无线电能接收器基于所述无线接收的电能向总线输出电能。所述装置具有开环DC?DC转换器和线性调节器。所述装置具有控制器，用于启用所述开环DC?DC转换器以使用所述总线上的所述电能对电池进行充电。所述控制器还用于：当正在使用所述开环DC?DC转换器对所述电池进行充电时，在使用所述接收线圈进行从所述无线电能接收器到所述电能的所述发射器的无线通信时，控制所述线性调节器以稳定所述无线电能接收器的所述输出处的所述总线中的电流，从而减少对无线充电发射器和接收器间通信的干扰。(An apparatus having a wireless power receiver including a receive coil for wirelessly receiving power and wirelessly communicating is described herein. The wireless power receiver outputs power to a bus based on the wirelessly received power. The apparatus has an open loop DC-DC converter and a linear regulator. The apparatus has a controller to enable the open loop DC-DC converter to charge a battery using the electrical energy on the bus. The controller is further configured to: controlling the linear regulator to stabilize current in the bus at the output of the wireless power receiver when using the receive coil for wireless communication from the wireless power receiver to the transmitter of the power while the open loop DC-DC converter is being used to charge the battery, thereby reducing interference with wireless charging transmitter and receiver-to-receiver communication.)

1. An apparatus for charging a battery using wirelessly received power, the apparatus comprising:

a wireless power Receiver (RX) comprising a receive coil, the wireless power RX for wirelessly receiving power using the receive coil and wirelessly communicating with a transmitter of the power, the wireless power RX having an output for outputting power to a bus based on the wirelessly received power;

an open-loop DC-DC converter having an input coupled to the bus and an output coupled to a terminal for coupling to the battery;

a linear regulator connected along a power path from the output of the wireless power RX to the terminals, a portion of the power path extending from the input of the open-loop DC-DC converter to the output of the open-loop DC-DC converter; and

a controller to enable the open-loop DC-DC converter to charge the battery using the power output by the wireless power RX to the bus;

the controller is further configured to: controlling the linear regulator to stabilize current in the bus at the output of the radio energy RX when wireless communication from the radio energy RX to the transmitter of the electrical energy is conducted using the receive coil while the open-loop DC-DC converter is being used to charge the battery, thereby reducing interference with wireless communication.

2. The apparatus of claim 1, wherein the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator does not actively limit current in the linear regulator unless the battery-powered load draws a transient current.

3. The apparatus of claim 1, wherein the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator actively limits current in the linear regulator regardless of whether the battery-powered load draws transient current.

4. The apparatus of any of claims 1-3, wherein the controller is configured to control the linear regulator based on a target current for charging the battery via the open-loop DC-DC converter.

5. The apparatus of any one of claims 1 to 4, wherein:

the linear regulator is located between the output of the radio energy RX and the input of the open-loop DC-DC converter.

6. The apparatus of any one of claims 1 to 4, wherein:

the linear regulator is located between the output of the open loop DC-DC converter and the terminal for coupling to the battery.

7. The apparatus of any of claims 1 to 6, wherein the linear regulator is integrated with a reverse current protection block for the power path.

8. The device of any one of claims 1 to 6, wherein the linear regulator is configured to provide overvoltage protection.

9. The apparatus of any one of claims 1 to 8, further comprising:

a closed loop DC-DC converter having an input coupled to the bus and an output for coupling to the terminal for coupling to the battery, the power path being a first power path, the closed loop DC-DC converter being connected along a second power path from the output of the wireless power RX to the terminal;

the controller is further configured to: selectively enabling one of the closed loop DC-DC converter and the open loop DC-DC converter each time the battery is charged using the power output to the bus from the wireless power RX.

10. The apparatus of claim 9, wherein:

the controller is further configured to enable the closed-loop DC-DC converter and disable the open-loop DC-DC converter to charge the battery in a constant-current closed-loop DC-DC converter stage and a constant-voltage closed-loop DC-DC converter stage; and

the controller is further configured to enable the open-loop DC-DC converter and disable the closed-loop DC-DC converter to charge the battery during a constant-current open-loop DC-DC converter stage and a constant-voltage open-loop DC-DC converter stage.

11. The apparatus according to any of claims 1 to 10, wherein the controller is further configured to control the linear regulator to stabilize the voltage of the bus at the output of the radio energy RX, thereby reducing the interference to communication.

12. A method for charging a battery using wirelessly received power, the method comprising:

wirelessly receiving power at a wireless power Receiver (RX) using a receive coil;

outputting power to a bus from an output of the wireless power RX based on the wirelessly received power;

using the receive coil for wireless communication from the radio energy RX to a transmitter of the radio energy;

enabling an open loop DC-DC converter to charge a battery using the power output by the wireless power RX to the bus, wherein the open loop DC-DC converter has an input coupled to the bus and an output coupled to a terminal for coupling to the battery; and

controlling a linear regulator to stabilize a current in the bus at the output of the wireless power RX when wireless communication is conducted from the wireless power RX to the transmitter using the receive coil while the battery is being charged using the open loop DC-DC converter, thereby reducing interference with wireless communication, wherein the linear regulator is connected in a power path from the output of the wireless power RX to the terminals, a portion of the power path extending from the input of the open loop DC-DC converter to the output of the open loop DC-DC converter.

13. The method of claim 12, wherein controlling the linear regulator comprises:

operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator does not actively limit current in the linear regulator unless the battery-powered load draws a transient current.

14. The method of claim 12, wherein controlling the linear regulator comprises:

determining a voltage on the bus at the output of the wireless power RX to determine a voltage drop of the linear regulator when the open loop DC-DC converter is being used to charge the battery, thereby placing the linear regulator in a current limiting mode regardless of whether transient current is being drawn by the battery powered load.

15. The method of any of claims 12 to 14, wherein controlling the linear regulator comprises:

controlling the linear regulator to limit current from the output of the open loop DC-DC converter based on a target battery charging current.

16. An apparatus for charging a battery using wirelessly received power, the apparatus comprising:

an electrical energy bus;

a wireless power Receiver (RX) including a receive coil, the wireless power RX for wirelessly receiving power using the receive coil and wirelessly communicating with a transmitter of the power, the wireless power receiver for outputting Direct Current (DC) power to the power bus based on the wirelessly received power;

a closed loop DC-DC converter having an input coupled to the power bus and an output for coupling to the battery;

an open-loop DC-DC converter having an input coupled to the power bus and an output for coupling to the battery;

a linear regulator coupled in series with the open loop DC-DC converter; and

a controller to: selectively enabling one of the closed-loop DC-DC converter and the open-loop DC-DC converter each time the battery is charged using the DC power output by the wireless power RX to the bus;

the controller is further configured to: controlling the linear regulator to stabilize current on the bus at the output of the radio energy RX when using the receive coil for wireless communication from the radio energy RX to the transmitter of the electrical energy while the open-loop DC-DC converter is being used to charge the battery, thereby reducing interference of transient load current with wireless communication.

17. The apparatus of claim 16, wherein the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator does not actively limit current unless the battery-powered load draws a transient current.

18. The apparatus of claim 16, wherein the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator actively limits current regardless of whether the battery-powered load is drawing transient current.

19. The apparatus of any of claims 16-18, wherein the controller is configured to control the linear regulator based on a target current used to charge the battery through the open-loop DC-DC converter.

20. The apparatus according to any one of claims 16 to 19, wherein:

the linear regulator is located between the output of the radio energy RX and the input of the open-loop DC-DC converter.

21. The apparatus according to any one of claims 16 to 19, wherein:

the linear regulator is located between the output of the open-loop DC-DC converter and the battery.

22. The apparatus of any of claims 16 to 21, wherein the linear regulator is configured to provide reverse current block protection.

23. The apparatus of any one of claims 16 to 21, wherein the linear regulator is configured to provide overvoltage protection.

24. The apparatus according to any one of claims 16 to 23, wherein:

the controller is further configured to enable the closed-loop DC-DC converter and disable the open-loop DC-DC converter during a constant-current closed-loop DC-DC converter stage and a constant-voltage closed-loop DC-DC converter stage; and

the controller is further configured to enable the open-loop DC-DC converter and disable the closed-loop DC-DC converter during a constant-current open-loop DC-DC converter stage and a constant-voltage open-loop DC-DC converter stage.

25. The apparatus of any of claims 16-24, wherein the transient load current is caused by: the amount of current drawn by the battery-powered load varies periodically while the open-loop DC-DC converter is being used to charge the battery.

26. A method for charging a battery using wirelessly received power, the method comprising:

wirelessly receiving power at a wireless power Receiver (RX) using a receive coil;

outputting Direct Current (DC) power to a power bus at an output of the radio power RX based on the wirelessly received power;

using the receive coil for wireless communication from the radio energy RX to a transmitter of the radio energy;

selectively enabling one of a closed loop DC-DC converter and an open loop DC-DC converter each time a battery coupled to an output of the closed loop DC-DC converter and an output of the open loop DC-DC converter is charged with the DC power output by the wireless power RX to the power bus; and

controlling a linear regulator coupled in series with the open-loop DC-DC converter to stabilize current on the power bus at the output of the wireless power RX when wireless communication is conducted from the wireless power RX to the transmitter using the receive coil while the open-loop DC-DC converter is being used to charge the battery, thereby reducing interference of transient load current with wireless communication.

27. The method of claim 26, wherein controlling the linear regulator coupled in series with the open-loop DC-DC converter comprises:

operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator does not actively limit current unless the battery-powered load draws a transient current.

28. The method of claim 26, wherein controlling the linear regulator coupled in series with the open-loop DC-DC converter comprises:

setting the output voltage of the radio energy RX to determine the voltage drop of the linear regulator when the open loop DC-DC converter is being used to charge the battery, thereby placing the linear regulator in a current limiting mode regardless of whether the battery powered load draws transient current.

29. The method of any of claims 26 to 28, wherein controlling the linear regulator coupled in series with the open loop DC-DC converter comprises:

controlling the linear regulator to limit the current from the output of the open-loop DC-DC converter based on a target battery charging current.

30. A wireless electronic device, comprising:

an electrical energy bus;

a wireless power Receiver (RX) including a receive coil, the wireless power RX configured to wirelessly receive power using the receive coil, wirelessly communicate with a transmitter of the wireless power using the receive coil, and output Direct Current (DC) power to the power bus based on the wirelessly received power;

a closed loop DC-DC converter having an input coupled to the power bus and an output coupled to a battery in the wireless electronic device;

an open-loop DC-DC converter having an input coupled to the power bus and an output coupled to the battery;

a linear regulator coupled in series with the open loop DC-DC converter;

an electronic assembly for: drawing current from the battery and/or drawing current from the output of the open loop DC-DC converter when the open loop DC-DC converter is being used to charge the battery; and

a controller to: selectively enabling one of the closed-loop DC-DC converter and the open-loop DC-DC converter each time the battery is charged using the DC power on the power bus; the controller is further configured to: controlling the linear regulator to stabilize current and voltage on the power bus at the output of the wireless power RX when the receive coil is being used for wireless communications while the open loop DC-DC converter is being used to charge the battery, thereby reducing interference caused by the electronic components drawing current from the battery.

31. The wireless electronic device of claim 30, wherein the controller is further configured to: controlling the linear regulator to prevent interference from periodic variations in an amount of current drawn by the electronic components when the receiving coil is used for communication from the wireless power RX to the transmitter of the power while the open loop DC-DC converter is being used to charge the battery.

32. The wireless electronic device of claim 30 or 31, wherein the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator does not actively limit current unless the electronic components draw transient currents.

33. The wireless electronic device of claim 30 or 31, wherein the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator actively limits current regardless of whether the electronic components draw transient current.

34. The wireless electronic device of any of claims 30-33, wherein:

the closed loop DC-DC converter comprises a buck charger; and

the open-loop DC-DC converter includes a switched capacitor charger.

35. The wireless electronic device of claim 34, wherein:

the controller is further configured to: starting the step-down charger and forbidding the switched capacitor charger in a constant-current step-down charger stage and a constant-voltage step-down charger stage; and

the controller is further configured to: and in the constant-current switch capacitor charger stage and the constant-voltage switch capacitor charger stage, starting the switch capacitor charger and forbidding the voltage reduction charger.

Technical Field

The present invention relates generally to wireless battery charging systems and methods of using the same.

Background

In a typical Qi standard wireless battery charging system, an adapter converts a power supply from an AC voltage to a DC voltage and provides the DC voltage to a wireless power Transmitter (TX). The wireless power TX wirelessly transmits power to a wireless power Receiver (RX) through inductive coupling, and the wireless power RX rectifies the power and provides a DC voltage to a charger. The charger charges the rechargeable battery through steady current or steady voltage.

Communications are used to control the operation of the system. In the Qi standard developed by Wireless Power Consortium (WPC), communication from the radio Power RX to the radio Power TX is accomplished by modulating a load seen by a coil of the radio Power RX, and communication from the radio Power TX to the radio Power RX is accomplished by modulating a frequency of a transmission Power signal. Both of the aforementioned types of communication are in-band communication. Communication between the wireless power TX and the adapter may be performed, for example, over wires in a Universal Serial Bus (USB) cable.

Disclosure of Invention

According to a first aspect of the present invention, there is provided an apparatus for charging a battery using wirelessly received power. The apparatus includes a wireless power Receiver (RX) including a receive coil. The wireless power RX is configured to wirelessly receive power using the receiving coil and wirelessly communicate with a transmitter of the power. The radio power RX has an output for outputting power to a bus based on the wirelessly received power. The apparatus has an open loop DC-DC converter having an input coupled to the bus and an output coupled to terminals for coupling to the battery. The apparatus has a linear regulator connected along a power path from the output of the wireless power RX to the terminal. A portion of the power path extends from the input of the open loop DC-DC converter to the output of the open loop DC-DC converter. The apparatus has a controller to enable the open loop DC-DC converter to charge the battery using the power output by the wireless power RX to the bus. The controller is further configured to: controlling the linear regulator to stabilize current in the bus at the output of the radio energy RX when wireless communication from the radio energy RX to the transmitter of the electrical energy is conducted using the receive coil while the open-loop DC-DC converter is being used to charge the battery, thereby reducing interference with wireless communication.

Optionally, in a second aspect and extensions of the first aspect, the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator does not actively limit current in the linear regulator unless the battery-powered load draws a transient current.

Optionally, in a third aspect and extensions of the first or second aspects, the controller is configured to: operating the linear regulator in the following mode when the open-loop DC-DC converter is being used to charge the battery: the linear regulator actively limits current in the linear regulator regardless of whether the battery-powered load draws transient current.

Optionally, in a fourth aspect and in a development of any of the first to third aspects, the controller is configured to control the linear regulator based on a target current for charging the battery by the open-loop DC-DC converter.

Optionally, in a fifth aspect and in a development of any of the first to fourth aspects, the linear regulator is located between the output of the radio energy RX and the input of the open-loop DC-DC converter.

Optionally, in a sixth aspect and in a development of any of the first to fourth aspects, the linear regulator is located between the output of the open loop DC-DC converter and the terminal for coupling to the battery.

Optionally, in a seventh aspect and in a development of any of the first to sixth aspects, the linear regulator is integrated with a reverse current protection block for the power path.

Optionally, in an eighth aspect and in a development of any of the first to sixth aspects, the linear regulator is for providing overvoltage protection.

Optionally, in a ninth aspect and in a extension of any of the first to eighth aspects, the apparatus further comprises a closed loop DC-DC converter having an input coupled to the bus and an output for coupling to the terminal for coupling to the battery. The power path is a first power path. The closed loop DC-DC converter is connected along a second power path from the output of the wireless power RX to the terminals. The controller is further configured to: selectively enabling one of the closed loop DC-DC converter and the open loop DC-DC converter each time the battery is charged using the power output to the bus from the wireless power RX.

Optionally, in a tenth aspect and in a development of the ninth aspect, the controller is further configured to enable the closed-loop DC-DC converter and disable the open-loop DC-DC converter to charge the battery in a constant-current closed-loop DC-DC converter stage and a constant-voltage closed-loop DC-DC converter stage. The controller is further configured to enable the open-loop DC-DC converter and disable the closed-loop DC-DC converter to charge the battery during a constant-current open-loop DC-DC converter stage and a constant-voltage open-loop DC-DC converter stage.

Optionally, in an eleventh aspect and in a extension of any of the first to tenth aspects, the controller is further configured to control the linear regulator to stabilize a voltage of the bus at the output of the radio energy RX, thereby reducing the interference to communications.

According to another aspect of the present invention, there is provided a method of charging a battery using wirelessly received power. The method includes wirelessly receiving power at a wireless power Receiver (RX) using a receive coil. The method comprises outputting power to a bus from an output of the wireless power RX based on the wirelessly received power. The method includes using the receive coil for wireless communication from the radio energy RX to the transmitter of radio energy. The method includes enabling an open loop DC-DC converter to charge a battery using the power output by the wireless power RX to the bus, wherein the open loop DC-DC converter has an input coupled to the bus and an output coupled to a terminal for coupling to the battery. The method comprises the following steps: controlling a linear regulator connected in a power path from the output of the radio energy RX to the terminal to stabilize a current in the bus at the output of the radio energy RX to reduce interference with wireless communications when the receiving coil is used for wireless communications from the radio energy RX to the transmitter while the open loop DC-DC converter is being used to charge the battery. A portion of the power path extends from the input of the open loop DC-DC converter to the output of the open loop DC-DC converter.

According to still another aspect of the present invention, there is provided an apparatus for charging a battery using wirelessly received power. The apparatus includes a power bus and a wireless power Receiver (RX) having a receive coil. The wireless power RX is configured to wirelessly receive power using the receiving coil and wirelessly communicate with a transmitter of the power. The wireless power receiver is configured to output Direct Current (DC) power to the power bus based on the wirelessly received power. The apparatus includes a closed loop DC-DC converter having an input coupled to the power bus and an output for coupling to the battery. The apparatus includes an open loop DC-DC converter having an input coupled to the electrical energy bus and an output for coupling to the battery. The apparatus includes a linear regulator coupled in series with the open-loop DC-DC converter. The apparatus includes a controller to: selectively enabling one of the closed loop DC-DC converter and the open loop DC-DC converter each time the battery is charged using the DC power output by the wireless power RX to the bus. The controller is further configured to: controlling the linear regulator to stabilize current on the bus at the output of the radio energy RX when using the receive coil for wireless communication from the radio energy RX to the transmitter of the electrical energy while the open-loop DC-DC converter is being used to charge the battery, thereby reducing interference of transient load current with wireless communication.

According to still another aspect of the present invention, there is provided a method of charging a battery using wirelessly received power. The method comprises the following steps: wirelessly receiving power at a wireless power Receiver (RX) using a receive coil; outputting Direct Current (DC) power to a power bus at an output of the radio power RX based on the wirelessly received power; using the receive coil for wireless communication from the radio energy RX to a transmitter of the radio energy; selectively enabling one of a closed loop DC-DC converter and an open loop DC-DC converter each time a battery coupled to an output of the closed loop DC-DC converter and an output of the open loop DC-DC converter is charged with the DC power output by the wireless power RX to the power bus; and controlling a linear regulator coupled in series with the open-loop DC-DC converter to stabilize current on the power bus at the output of the wireless power RX when wireless communication is conducted from the wireless power RX to the transmitter using the receive coil while the open-loop DC-DC converter is being used to charge the battery, thereby reducing interference of transient load currents with wireless communication.

According to yet another aspect of the invention, a wireless electronic device is provided. The wireless electronic device includes a power bus and a wireless power Receiver (RX) having a receive coil. The wireless power RX is configured to wirelessly receive power using the receiving coil, wirelessly communicate with a transmitter of the wireless power using the receiving coil, and output Direct Current (DC) power to the power bus based on the wirelessly received power. The wireless electronic device includes a closed loop DC-DC converter having an input coupled to the power bus and an output coupled to a battery in the wireless electronic device. The wireless electronic device includes an open loop DC-DC converter having an input coupled to the power bus and an output coupled to the battery. The wireless electronic device includes a linear regulator coupled in series with the open-loop DC-DC converter. The wireless electronic device includes electronic components to: drawing current from the battery, and drawing current from the output of the open-loop DC-DC converter when the open-loop DC-DC converter is being used to charge the battery. The wireless electronic device includes a controller to: selectively enabling one of the closed loop DC-DC converter and the open loop DC-DC converter each time the battery is charged using the DC power on the power bus. The controller is further configured to: controlling the linear regulator to stabilize current and/or voltage on the power bus at the output of the wireless power RX when the open loop DC-DC converter is being used to charge the battery when the receive coil is being used for wireless communications, thereby reducing interference caused by the electronic components drawing current from the battery.

Embodiments of the present technology described herein improve upon existing wireless battery charging systems. Such embodiments may be used to reduce or eliminate interference to wireless communications from the radio RX to the radio transmitter. The disturbance may be caused by transient currents drawn by the battery-powered load. Such transient currents may cause load variations on the radio energy RX, which may interfere with wireless communication when the open-loop DC-DC converter is used to charge the battery. These embodiments reduce or eliminate the interference of transient load currents with wireless communications when an open loop DC-DC converter is being used to charge the battery.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

Drawings

Aspects of the present invention are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.

Fig. 1 illustrates an example wireless battery charging system.

Fig. 2 shows further details of the example wireless battery charging system introduced in fig. 1.

Fig. 3 illustrates a wireless battery charging system in accordance with an embodiment of the present technology.

FIG. 4 shows exemplary details of an electronic device that may implement methods and teachings consistent with the present invention.

Fig. 5 shows a graph illustrating an example wireless battery charging profile (chargingprofile) of the wireless battery charging system shown in fig. 3.

Fig. 6 is a state diagram illustrating how the wireless battery charging system shown in fig. 3 operates in accordance with certain embodiments of the present technique.

Fig. 7 is a diagram of a system for charging a battery.

Fig. 8A-8C are graphs of various waveforms showing how a load may interfere with communications in the system of fig. 7 when an open loop DC-DC converter is used to charge a battery.

Fig. 9A and 9B are graphs showing how transient current drawn by a load may affect wireless communications when using the system of fig. 7.

Fig. 10A to 10C are diagrams of embodiments of a wireless power RX and charger having a linear regulator arranged in a different manner with respect to other components.

Fig. 11A is a flow diagram of one embodiment of a process for operating the wireless power RX and charger using an open loop DC-DC converter.

Fig. 11B is a flow diagram of one embodiment of a process for operating the wireless power RX and charger using a closed loop DC-DC converter and an open loop DC-DC converter.

FIG. 12A is a graph depicting one embodiment of operating a linear regulator in the following mode: the linear regulator does not actively limit current unless the load draws a transient current.

FIG. 12B is a graph depicting one embodiment of operating a linear regulator in the following mode: linear regulators actively limit current whether or not the load draws transient current.

Fig. 13A depicts one embodiment where the wireless power RX and charger has a linear regulator/ARC that provides ARC protection.

Fig. 13B depicts one embodiment of a wireless power RX and charger having a linear regulator/OVP that provides OVP.

Detailed Description

The present invention will now be described in conjunction with the appended drawings, which generally relate to a wireless battery charging system for wirelessly charging a rechargeable battery of an electronic device including a load powered by the battery, and a method of using the same.

Fig. 1 shows an example wireless battery charging system 100, which may be, but is not limited to, a Qi standard wireless battery charging system. The Qi standard is an open interface standard developed by the Wireless Power Consortium (WPC) that defines Wireless Power transfer using inductive charging over distances up to 4 centimeters (1.6 inches). The Qi standard wireless battery charging system typically uses a charging pad and a compatible battery powered device placed on the charging pad to be charged by resonant inductive coupling.

Referring to fig. 1, an example wireless battery charging system 100 is shown including an adapter 112, a wireless power Transmitter (TX)122, and a wireless power Receiver (RX) and charger 142. As can be appreciated from fig. 1, the wireless power RX and charger 142 is shown as part of the electronic device 132, the electronic device 132 further including a rechargeable battery 152 and a load 162 powered by the battery 152. Since the electronic device 132 is powered by a battery, the electronic device 132 may also be referred to as a battery-powered device 132. The load 162 may include, for example, one or more processors, displays, transceivers, and/or the like, depending on the type of electronic device 132. The electronic device 132 may be, but is not limited to, a smartphone, a tablet computer, a notebook computer, or the like. Battery 152, such as a lithium ion battery, may include one or more cells with external connections for powering a load 162 of electronic device 132.

The adapter 112 converts an Alternating Current (AC) voltage received from the AC power source 102 into a Direct Current (DC) input voltage (Vin). The AC power source 102 may be provided by a wall outlet, an electrical outlet, or a generator, but is not limited thereto. The wireless power TX122 accepts an input voltage (Vin) from the adapter 112 and wirelessly transmits power to the wireless power RX and charger 142 based on the input voltage. The wireless power TX122 may be electrically coupled to the adapter 112 by a cable that includes a plurality of wires, one or more of which may be used to provide an input voltage (Vin) from the adapter 112 to the wireless power TX122, and one or more of which may provide a communication channel between the adapter 112 and the wireless power TX 122. The communication channel may support wired two-way communication between the adapter 112 and the wireless power TX 122. The cable that electrically couples the adapter 112 to the wireless power TX122 may include a ground for a common Ground (GND). In fig. 1, the cable between the adapter 112 and the wireless power TX122 is generally represented by a double-headed arrow extending between the adapter 112 and the wireless power TX 122. This cable may be, for example, but not limited to, a Universal Serial Bus (USB) cable.

The wireless power RX and charger 142 wirelessly receives power from the wireless power TX122 through inductive coupling and charges the battery 152 using the received power. The wireless power RX and charger 142 may also be in bidirectional wireless communication with the wireless power TX122 using in-band communication defined by the Qi standard. In fig. 1, the double-headed arrows extending between the wireless power TX122 and the wireless power RX and charger 142 are used to generally represent wireless power transfer and communication therebetween.

Fig. 2 shows further details of the wireless battery charging system 100 introduced in fig. 1. For greater simplicity, the load 162 powered by the battery 152 is not shown in fig. 2, nor is the electronic device 132 including the wireless power RX and the charger 142 shown. Referring to FIG. 2, the adapter 112 is shown as including an adapter controller 214. The adapter 112 may include an AC/DC converter (not expressly shown) that converts an AC voltage provided by the power supply 102 to a DC input voltage (Vin) provided by the adapter 112 to the wireless power TX 122. Such an AC/DC converter may be or may include, for example, but not limited to, a full wave rectifier. The adapter controller 214 may include, for example, a processor and a transceiver to transmit and receive communication signals to and from the wireless power TX 122.

In fig. 2, the wireless power TX122 is shown to include a Power Delivery (PD) controller 224, a wireless power transmitter integrated circuit (TXIC) 226, and a half-bridge inverter 228. The half-bridge inverter 228 is shown connected between a high voltage rail (at the input voltage (Vin)) and Ground (GND). The PD controller 224 may include, for example, a processor and a transceiver that transmits and receives wireless communication signals to and from the adapter 112. The functions of the PD controller may sometimes be integrated into the TXIC 226. The wireless power TXIC226 is shown receiving an input voltage (Vin) from the adapter 112 and controlling the switches of the half-bridge inverter 228 (S1 and S2). Switches S1 and S2 open and close at a desired frequency to generate an alternating signal at the output between the switches. The output of the inverter 228 is connected to an inductor L1 through a resonant capacitor C1. Since inductor L1 acts as a transmit coil, inductor L1 may also be referred to as a transmit coil. As is known in the art, a full-bridge inverter including four switches may be used in place of the half-bridge inverter 228. Other variations are also possible, as known in the art. The TXIC may include, for example, a processor and a transceiver that transmits and receives communication signals to and from the radio power RXIC and the charger 142.

Still referring to fig. 2, the wireless power RX and charger 142 is shown to include an Application Processor (AP) 244, a wireless power receiver integrated circuit (RXIC) 246, and a buck charger 248. The radio power RXIC246 is connected to the inductor L2 through a resonant capacitor C2. Since inductor L2 acts as a receive coil, inductor L2 may also be referred to as a receive coil. The inductors L1 and L2 provide inductive coupling between the wireless power TX122 and the wireless power RX and charger 142, and more specifically, between the wireless power TXIC226 and the wireless power RXIC 246. Inductive coupling may be used to transfer power from the wireless power TX122 to the wireless power RX and charger 142 and provide in-band bidirectional wireless communication between the two. In the illustrated embodiment, a single transmit coil is used to wirelessly transfer power from the wireless power TXIC226 to the wireless power RXIC246, but more than one transmit coil may be used to wirelessly transfer power. Similarly, it is also possible to receive power wirelessly at the inductively coupled receiving side using more than one receiving coil. Other variations are also possible, as known in the art.

The wireless power RXIC246 converts the AC voltage supplied thereto by the inductor L2 to a DC output voltage (Vout). The DC output voltage (Vout) is provided to a buck charger 248. The buck charger 248 may step down the output voltage (Vout) to an appropriate battery charging voltage (Vbat) for charging the battery 152. For example, Vout may be 10 volts (Volt, V) and Vbat may be 4.2V. As another example, Vout may be 10V and Vbat may be 3.5V. These are just a few examples and are not intended to be limiting as Vout and Vbat can have countless different values. In alternative embodiments, it is also possible for the buck charger to step up the output voltage (Vout), i.e., as a boost charger, or to maintain the output voltage (Vout) so that the battery charging voltage (Vbat) is the same as Vout.

The buck charger 248 may also be referred to as a buck converter, which is an example of a closed loop charger because the voltage and/or current at its output (i.e., at the terminal that generates Vbat, which may be referred to as the Vbat terminal) is regulated based on feedback generated by the buck charger 248 itself. The AP 244, which may also be referred to as a controller, may send and receive communication signals to and from the wireless power RXIC246 and the buck charger 248. In some embodiments, the AP 244 may communicate with the radio RXIC246 and the buck charger 248 using Inter-Integrated Circuit (I2C) serial bus communication, although other communication interfaces and protocols may be used. AP 244 may be, for example, a processor of electronic device 132, which may also be used to run applications, control communications, and the like, but is not limited to such. The wireless power RX and charger 142 may also include a controller, such as a PD controller, dedicated to controlling battery charging.

The buck charger 248 is shown to include a voltage input terminal labeled Vbus and a voltage output terminal labeled Vbat. The voltage output terminal (labeled Vbat) is shown as a terminal connected to a rechargeable battery 152, which rechargeable battery 152 may also be referred to herein simply as battery 152. The step-down charger 248 may charge the rechargeable battery 152 by regulated current or regulated voltage.

As mentioned above, the maximum efficiency of a step-down charger (e.g., 248) is typically only ninety percent, resulting in wasted energy. This waste of energy can lead to heating of battery powered devices (e.g., 132) such as smartphones where the step-down charger is located, which is undesirable. Furthermore, this inefficiency results in longer charging times than are required for high efficiency.

Certain embodiments of the present technology described below may be used to improve the overall efficiency of a wireless battery charging system. These embodiments are advantageous because they can reduce energy waste, thereby mitigating heating up of battery-powered devices (e.g., 132) such as smartphones where the step-down charger is located. In addition, these embodiments may reduce the time required to fully charge a battery (e.g., 152).

Fig. 3 illustrates a wireless battery charging system 300 in accordance with an embodiment of the present technology. In fig. 3, elements that are the same or similar to elements already discussed in connection with fig. 1 and 2 are labeled the same and in some cases are not discussed in detail again, as reference may be made to the discussion of fig. 1 and 2 above.

Referring to fig. 3, an example wireless battery charging system 300 is shown including an adapter 112, wireless power TX122, and wireless power RX and charger 342. The wireless power RX and charger 342 may be included in an electronic device (such as, but not limited to, a smartphone, tablet, or laptop computer) that also includes a rechargeable battery 152 and a load 162 powered by the battery 152. The adapter 112 includes an adapter controller 214 and may include an AC/DC converter (not expressly shown) that converts an AC voltage provided by the power supply 102 to a DC input voltage (Vin) provided by the adapter 112 to the wireless power TX 122. The adapter controller 214 may include, for example, a processor and a transceiver to transmit and receive communication signals to and from the wireless power TX 122.

Wireless power TX122 includes a PD controller 224, a wireless power TXIC226, and an inverter 228. The PD controller 224 may include, for example, a processor and a transceiver that transmits and receives wireless communication signals to and from the adapter 112. The wireless power TXIC226 may accept an input voltage (Vin) from the adapter 112 and control the switches (S1 and S2) of the inverter 228 to generate an alternating signal at its output. Alternatively, another DC-DC converter may be placed between the adapter 112 and the wireless power TX122, and the adapter 112 may output a fixed DC voltage that may be controlled to regulate the input voltage (Vin) provided to the wireless power TX 122. The output of the inverter 228 is connected to an inductor L1 (which may also be referred to as a transmit coil) through a resonant capacitor C1. Instead of the half-bridge inverter 228, a full-bridge inverter comprising four switches may be used, as is known in the art. Other variations are also possible, as known in the art.

Still referring to fig. 3, the wireless power RX and charger 342 is shown to include a Power Receiver (PR) controller 344, a wireless power RXIC246, a closed loop DC-DC converter 348, an open loop DC-DC converter 350, and a linear regulator 360. In fig. 3, the radio power RXIC246 is connected to an inductor L2 (which may also be referred to as a receiving coil) through a resonant capacitor C2. The inductors L1 and L2 provide inductive coupling between the wireless power TXIC226 and the wireless power RXIC246 for transferring power from the wireless power TX122 to the wireless power RX and the charger 342, and for providing bidirectional wireless communication therebetween. The wireless power RXIC246 outputs power to the power bus 354a based on the power it receives. The wireless power RXIC246 outputs a DC voltage (Vbus) and a DC current (Ibus) to the power bus 354 a. In the illustrated embodiment, a single transmit coil is used to wirelessly transfer power from the wireless power TXIC226 to the wireless power RXIC246, but more than one transmit coil may be used to wirelessly transfer power. Similarly, it is also possible to receive power wirelessly at the inductively coupled receiving side using more than one receiving coil. Other variations are also possible, as known in the art.

Since the receive coil L2 is simultaneously used to receive power from the radio power TXIC226, the use of the receive coil L2 to communicate between the radio power TXIC226 and the radio power RXIC246 is referred to as in-band communication. Embodiments disclosed herein improve in-band communication. Specifically, in an embodiment, in-band communication from the radio power RXIC246 to the radio power TXIC226 is improved by controlling the regulator 360 while the open loop DC-DC converter 350 is being used to charge the battery 152.

In one embodiment, the closed loop DC-DC converter 348 is a buck charger. In one embodiment, the closed loop DC-DC converter 348 is a boost charger. In one embodiment, the closed loop DC-DC converter 348 is a buck-boost charger. In one embodiment, the open-loop DC-DC converter 350 is a switched capacitor charger. In one embodiment, the open-loop DC-DC converter 350 is a load switch charger. In one embodiment, the open-loop DC-DC converter 350 is a flash charger. The inclusion and selective use of the open loop DC-DC converter 350 improves the overall efficiency of the wireless battery charging system 300, which effectively mitigates the warming of the battery-powered devices (where the DC-DC converters 348 and 350 are located) and effectively shortens the overall time required to fully charge the rechargeable battery (e.g., 152). For example, the efficiency of a typical switched capacitor charger (e.g., 350) is 97% higher than the efficiency of a typical buck charger (e.g., 348).

In accordance with certain embodiments of the present technique, only one of the two chargers 348 and 350 is operating during any given phase of the battery charging process (also referred to as a charging regime). For a closed-loop DC-DC converter 348 (e.g., a buck converter), the voltage and/or current at its output (i.e., at the Vbat terminal) is regulated based on feedback generated by the closed-loop DC-DC converter 348 itself. In contrast, for the open-loop DC-DC converter 350, the voltage and/or current at its output (i.e., at the Vbat terminal) is not regulated based on feedback generated by the open-loop DC-DC converter 350 itself. The closed-loop DC-DC converter 348 may have better current and voltage regulation capabilities and may be used for low power charging phases. The open-loop DC-DC converter 350 has no current and voltage regulation capability and can be used for high power charging phases. Note that the term Vbat is used to refer to both the output terminals of the DC-DC converters (348 and 350) and to the battery charge voltage output at that terminal, the specific usage of which may be understood from its context of use.

In some embodiments, the PR controller 344 is used to control the system 300 when the open loop DC-DC converter 350 is used to charge the battery 152. When the open-loop DC-DC converter 350 is operating, the PR controller 344 controls the entire wireless battery charging system to operate in the closed-loop mode. In some embodiments, when an open loop DC-DC converter 350 is used, the PR controller 344 regulates the battery charging current (Ichg) or charging voltage. In the constant current charging state, when the open loop DC-DC converter 350 is used, the PR controller 344 adjusts the battery charging current to follow the target value. In the constant voltage charging state, when the open-loop DC-DC converter 350 is used, the PR controller 344 adjusts the battery charging voltage to follow the target value. In some embodiments, the functionality of the PR controller 344 is implemented in an Application Processor (AP).

In one embodiment, when the open loop DC-DC converter 350 is used, the PR controller 344 instructs the radio power RXIC246 to transmit information to the radio power TXIC226 in order to operate the entire wireless battery charging system in a closed loop mode. For example, this communication is used to create a value of Vin at the input of the radio power TXIC 226. The PR controller 344 may also regulate the voltage (Vbus) at the output of the wireless power RXIC 246. Note that if wireless communication between the radio energy RXIC246 and the radio energy TXIC226 is affected, control of the open loop DC-DC converter 350 may also be affected. When the open-loop DC-DC converter 350 is used to charge the battery 152, the embodiments disclosed herein prevent the load 162 from interfering with this wireless communication.

The load 162 is depicted as drawing a load current (Iload). When the battery 152 is not being charged, the battery 152 provides a load current (Iload) to the load 162. When the open-loop DC-DC converter 350 is being used to charge the battery 152, the open-loop DC-DC converter 350 and/or the battery 152 may provide a load current (Iload) to the load 162. When the open-loop DC-DC converter 350 is charging the battery 152, the transient current drawn by the load 162 may interfere with communications from the wireless power RXIC246 to the wireless power TX 122.

As described in detail below, in an embodiment, the use of the linear regulator 360 reduces "load disturbance" to communications from the radio power RXIC246 to the radio power TXIC226 when the open loop DC-DC converter 350 is used to charge the battery 152. The phrase "reducing load interference" includes completely eliminating load interference. "load disturbance" refers to a disturbance caused at least indirectly by the transient current drawn by load 162. In some embodiments, a linear regulator 360 is used to stabilize Ibus flowing in the power bus 354a at the output of the wireless power RXIC 246. In some embodiments, a linear regulator 360 is used to stabilize Vbus on the power bus 354a at the output of the wireless power RXIC 246. In some embodiments, the linear regulator 360 is used to stabilize Ibus in the power bus 354a at the output of the wireless power RXIC246 and Vbus on the power bus 354a at the output of the wireless power RXIC 246. Stabilizing Ibus and/or Vbus at the output of the wireless power RXIC246 reduces or prevents load disturbances when wireless communication is conducted from the wireless power RXIC246 to the wireless power TXIC226 using the receive coil L2 while the open loop DC-DC converter 350 is being used to charge the battery 152. In other words, stabilizing Ibus and/or Vbus at the output of the wireless power RXIC246 improves wireless communication using the receive coil L2 when the open loop DC-DC converter 350 is being used to charge the battery 152. Thus, in-band communication is improved.

In one embodiment, linear regulator 360 is a low dropout regulator. In one embodiment, the linear regulator 360 is a linear regulator. Linear regulators may be used to maintain a constant voltage level at their input and/or output. In one embodiment, linear regulator 360 includes a MOSFET that operates in the linear region. In one embodiment, a linear regulator may be used to regulate the current through linear regulator 360. Thus, in some embodiments, the linear regulator 360 may be referred to as a current regulator.

Linear regulator 360 has an input (Vin), an output (Vout), and a regulated input (Reg). In one embodiment, the linear regulator 360 is able to regulate its current by changing the internal resistance of the linear regulator 360, which increases the voltage drop between Vin and Vout. In one embodiment, when there is no dynamic load on linear regulator 360, the regulation in linear regulator 360 is inactive. In one embodiment, when the linear regulator 360 is not actively regulating, the voltage drop between its input (Vin) and output (Vout) is very low. When there is a dynamic load on linear regulator 360 (e.g., transient current drawn from load 162), the output voltage of linear regulator 360 may change over time. In one embodiment, the linear regulator 360 enters an active regulation mode in response to a dynamic load. In one embodiment, when actively regulating, the voltage drop of the linear regulator 360 increases to offset the change in its output voltage. In one embodiment, the linear regulator 360 stabilizes the current and voltage at its input (Vin) when actively regulating. Thus, in one embodiment, linear regulator 360 may prevent variations in voltage and/or current at its output (Vout) from propagating to its input (Vin). Thus, the linear regulator 360 may stabilize Ibus on the power bus 354a and/or Vbus on the power bus 354a at the output of the wireless power RXIC 246.

In one embodiment, when the open loop DC-DC converter 350 is being used to charge the battery 152, the PR controller 344 is used to operate the linear regulator 360 in the following mode: the linear regulator 360 does not actively limit current in the linear regulator 360 unless the load 162 draws a transient current.

In one embodiment, the linear regulator 360 regulates the current passing from the input (Vin) to the output (Vout) of the linear regulator 360 without allowing the current to exceed the target current level. In one embodiment, the target current magnitude approximates the target current magnitude for charging the battery 152 using the open loop DC-DC converter 350. In one embodiment, the target current level is slightly higher than the target current level for charging the battery 152. In one embodiment, the PR controller 344 sends a signal to a linear regulator input (Reg) to determine the target current magnitude. Note that preventing the current through the linear regulator 360 from exceeding the target current magnitude may also prevent the current (Ibus) in the power bus 354a at the output of the wireless power RXIC246 from exceeding the target current magnitude, a technique for stabilizing Ibus in the power bus 354a at the output of the wireless power RXIC 246.

In one embodiment, when the open loop DC-DC converter 350 is being used to charge the battery 152, the PR controller 344 is used to operate the linear regulator 360 in the following mode: the linear regulator 360 actively limits current in the linear regulator 360 regardless of whether the load 162 is drawing transient current. In one embodiment of the "active regulation mode", the voltage drop (between Vin and Vout) of the linear regulator 360 is about 50-100 millivolts. This voltage drop is a condition where load 162 does not draw transient current. When load 162 draws a transient current, the voltage drop of linear regulator 360 may decrease to counteract the transient current. Note that 50-100 millivolts through linear regulator 360 in the active regulation mode (load 162 does not draw transient current) is an example. The voltage may be less than 50 millivolts or greater than 100 millivolts when the load 162 is not drawing transient current.

In one embodiment, to achieve this "active regulation mode," PR controller 344 estimates a target voltage at the output of regulator 360 based on a target battery voltage (Vbat), estimates a target current at the input of open loop DC-DC converter 350 (e.g., an open loop charger), and an equivalent impedance between the output of regulator 360 and terminal 352. Then, the PR controller 344 sets the target voltage to the target voltage of the regulator. The regulator 360 will adjust its internal resistance to maintain its output voltage at the set voltage target. The PR controller 344 then sets the output voltage of the RXIC246 slightly higher (e.g., 50-100 millivolts higher) than the estimated target voltage, which is set to the regulated target voltage output of the regulator. The linear regulator 360 will then operate in the active regulation mode.

The linear regulator 360 is connected in a power path extending from the output of the wireless power RXIC246 to the terminal 352 connected to the battery 152. The power path is used to transfer DC power from the output of the wireless power RXIC246 to the battery 152. The power path includes physical components that are present whether or not power is currently being transmitted through the power path. A portion of this power path extends from the input (Vbus) of the open loop DC-DC converter 350 to the output (Vbat) of the open loop DC-DC converter 350.

It can also be said that the linear regulator 360 is coupled in series with the open-loop DC-DC converter 350. The term "coupled in series" as used herein means: when the battery 152 is being charged using the open loop DC-DC converter 350, there is a current path from the output of the linear regulator 360 (Vout) to the input of the open loop DC-DC converter 350 (Vbus) or a current path from the output of the open loop DC-DC converter 350 (Vbat) to the input of the linear regulator 360 (Vin). The power path includes physical components (which may include a power bus 354b, conductive lines, etc.) that are present whether or not current is currently flowing through the power path. There may be one or more components between the linear regulator 360 and the open loop DC-DC converter 350 while still providing a current path. Thus, the series coupling does not require a direct physical connection between the linear regulator 360 and the open-loop DC-DC converter 350. In fig. 3, the output (Vout) of the linear regulator 360 is connected to the input (Vbus) of the open-loop DC-DC converter 350 to provide current from the linear regulator 360 to the open-loop DC-DC converter 350. Note that in some embodiments, the open loop DC-DC converter 350 may increase the current. In other words, in one embodiment, the current at the output (Vbat) of the open loop DC-DC converter 350 is greater than the current at the input (Vbus) of the open loop DC-DC converter 350. Thus, the output currents of two components coupled in series do not have to have the same magnitude. In another example, the input currents of two components coupled in series do not have to be of the same magnitude.

In fig. 3, a linear regulator 360 is located between the output of the radio energy RXIC246 and the input of the open loop DC-DC converter 350. Thus, a portion of the power bus 354b is located between the output of the linear regulator 360 and the open loop DC-DC converter 350. However, the linear regulator 360 may be located elsewhere in the wireless power RX and charger 342. Fig. 10A-10C depict various embodiments to show other possible locations for the linear regulator 360 in the wireless power RX and charger 342. When the regulator 360 divides the power bus into two portions, these two portions are labeled 354a and 354b in the figure. When the regulator 360 is located on the battery 152 side of the open loop DC-DC converter 350, the power bus is labeled "354" in the figure.

FIG. 4 is an example electronic device 132 in which embodiments may be practiced. The electronic device 132 may be a wireless electronic device (e.g., a cell phone), etc., but may also be other devices in other examples, such as a desktop computer, a laptop computer, a tablet computer, a handheld computing device, an automotive computing device, and/or other computing devices. As shown in fig. 4, the electronic device 132 is shown to include a load 162, the load 162 including various electronic components including at least one transmitter 402, at least one receiver 404, a memory 406, at least one processor 408, and at least one input/output device 412. Processor 408 may perform various processing operations for electronic device 132. For example, processor 408 may perform signal coding, data processing, power control, input/output processing, or any other function that enables operation of electronic device 132. Processor 408 may include any suitable processing or computing device for performing one or more operations. For example, the processor 408 may include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

The transmitter 402 may be used to modulate data or other content for transmission over at least one antenna 410. The transmitter 402 may also be used to amplify, filter, and frequency convert the RF signals before providing them to the antenna 410 for transmission. Transmitter 402 may include any suitable structure for generating a wireless transmission signal.

The receiver 404 may be used to demodulate data or other content received by the at least one antenna 410. The receiver 404 may also be used to amplify, filter, and frequency convert RF signals received via the antenna 410. In some embodiments, the receiver 404 is an RF signal receiver. Receiver 404 may include any suitable structure for processing wirelessly received signals. The antenna 410 may include any suitable structure for transmitting and/or receiving wireless signals. The same antenna 410 may be used for transmitting and receiving RF signals, or different antennas 410 may be used for transmitting and receiving signals.

It may be appreciated that one or more transmitters 402 may be used in the electronic device 132, one or more receivers 404 may be used in the electronic device 132, and one or more antennas 410 may be used in the electronic device 132. Although shown as separate blocks or components, the at least one transmitter 402 and the at least one receiver 404 may be combined into one transceiver. Thus, instead of showing a single block for the transmitter 402 and a single block for the receiver 404, a single block for the transceiver may also be shown in fig. 4.

The electronic device 132 also includes one or more input/output devices 412. Input/output devices 412 facilitate interaction with a user. Each input/output device 412 includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keys, keyboard, display, or touch screen.

Further, the electronic device 132 includes at least one memory 406. Memory 406 stores instructions and data used, generated, or collected by electronic device 132. For example, the memory 406 may store software or firmware instructions executed by the processor 408 and data for reducing or eliminating interference in the incoming signal. Each memory 406 includes any suitable volatile and/or non-volatile storage and retrieval device. Any suitable type of memory may be used, such as Random Access Memory (RAM), Read Only Memory (ROM), hard disk, optical disk, Subscriber Identity Module (SIM) card, memory stick, Secure Digital (SD) memory card, and the like.

As the wireless power RX and charger 342 charges the battery 152, the load 162 may draw transient currents. These transient currents may be provided by the battery 152 and/or the wireless power RX and charger 342. The wireless power RX and charger 342 may communicate with the wireless power TX122 while charging the battery 152. More specifically, the wireless power RX and charger 342 may transmit information to the wireless power TX122 using the receiving coil L2. When the open-loop DC-DC converter 350 is charging the battery 152, the transient current drawn by the load 162 may interfere with communications from the wireless power RX and charger 342 to the wireless power TX 122. Embodiments disclosed herein reduce this communication interference due to load 162 drawing transient currents.

Fig. 5 illustrates an example charging regime for a wireless battery charging system 300 in accordance with an embodiment of the present technology. More specifically, the graph in fig. 5 includes a horizontal axis (i.e., x-axis) and a left side (at the lower portion) corresponding to the battery charging current (Ichg) corresponding to time, and a vertical axis (i.e., y-axis) corresponding to the output voltage (Vbus) of the radio power RXIC246 in fig. 3. The right vertical axis (i.e., the y-axis) corresponds to the battery charging voltage (Vbat). The battery charging current (Ichg) is the current provided to the battery at the Vbat terminal of the enabled one of the DC-DC converters 348 or 350 in fig. 3. The battery charge voltage (Vbat) is the voltage provided to the battery 152 at the Vbat terminal of the enabled one of the DC-DC converters 348 or 350 in fig. 3. In fig. 5 and other figures, the following abbreviations are sometimes used: SC: a switched capacitor (switched capacitor); CC: constant current (constantcurrent); CV: constant voltage (constant voltage); and (3) OVP: over voltage protection (overvoltage protection). In the example of fig. 5, the closed-loop DC-DC converter 348 is a buck converter and the open-loop DC-DC converter 350 is a switched-capacitor converter.

As can be appreciated from fig. 5, the charging regime shown in this figure includes five charging phases, including a pre-charge phase (between times T0 and T1), a constant current buck phase (between times T1 and T2), a constant current switched capacitor phase (between times T2 and T3), a constant voltage switched capacitor phase (between times T3 and T4), and a constant voltage buck phase (between times T4 and T5). The constant current step down phase (between times T1 and T2) may be more generally referred to as a constant current closed loop charging phase; the constant current switched capacitor phase (between times T2 and T3) may be more generally referred to as the constant current open loop charging phase; the constant voltage switched-capacitor phase (between times T3 and T4) may be more generally referred to as the constant voltage open loop charging phase; the constant voltage buck phase (between times T4 and T5) may be more generally referred to as a constant voltage closed loop charging phase. The waveform labeled 502 illustrates an example of how the output voltage (Vbus) of the radio power RXIC246 of fig. 3 changes from one phase to the next; the waveform labeled 504 illustrates an example of how the battery charge voltage (Vbat) changes from one phase to the next; the waveform labeled 506 illustrates an example of how the battery charging current (Ichg) changes from one phase to the next.

The waveform labeled 502 shows that the voltage (Vbus) on the power bus 354 at the output of the wireless power RXIC246 remains constant (i.e., 5V) during the pre-charge phase (between times T0 and T1) and the constant current buck phase (between times T1 and T2). The output voltage (Vbus) is shown to rise from 5V to about 7.2V at time T2, and then gradually from 7.2V to about 8.4V during the constant current switched capacitor phase (between times T2 and T3). The output voltage (Vout) is then held at about 8.4V for a portion of the constant voltage switched-capacitor phase (between times T3 and T4), and then stepped down to about 8.2V for the remainder of the constant voltage switched-capacitor phase. The output voltage (Vbus) is shown to drop from 8.2V back to 5V at time T4, remaining at 5V during the constant voltage buck phase (between times T4 and T5).

Still referring to fig. 5, the waveform labeled 504 shows the battery charge voltage (Vbat) steadily rising from about 3V to about 3.5V at a first rate during the pre-charge phase (between times T0 and T1) and the constant current buck phase (between times T1 and T2). The battery charge voltage (Vbat) is shown to steadily rise from about 3.5V to about 4.2V at a second rate (greater than the first rate) during the constant current switched capacitor phase (between times T2 and T3). The battery charge voltage (Vbat) rises very slowly to the battery Over Voltage Protection (OVP) level during the constant voltage switched capacitor phase (between times T3 and T4), then falls slightly, then rises slowly again to the battery OVP level. During the constant voltage step down phase (between times T4 and T5), the battery charge voltage (Vbat) is shown to remain unchanged (slightly below the battery OVP level).

The waveform labeled 506 shows the battery charging current (Ichg) remaining at about 0.2 amps (Amp, a) during the pre-charge phase (between times T0 and T1). At time T1, the cell current (Ichg) jumps to about 1A and remains at about 1A during the constant current buck phase (between times T1 and T2). During the constant current switched capacitor phase (between times T2 and T3), the battery charging current (Ichg) is shown to be sawtooth-shaped between about 4A to 3.7A. During the constant voltage switched capacitor phase (between times T3 and T4), the battery charging current (Ichg) drops parabolically from about 4A to about 2A, and the battery charging current (Ichg) decreases briefly when the battery charging voltage (Vbat) reaches the OVP level. During the constant voltage step down period (between times T4 and T5), the battery charging current (Ichg) is shown to decrease parabolically from about 2A to an end current near 0A.

Fig. 6 is a state diagram illustrating how the wireless battery charging system shown in fig. 3 operates in accordance with certain embodiments of the present technique. Referring to fig. 6, after start 602, the battery charging current limit (Ichg _ lim) is set equal to the pre-charge current limit (Ilim _ pre) and the buck converter (248 in fig. 3) is enabled. State 604 corresponds to a pre-charge phase in which a closed loop charger 348 (e.g., a buck charger) pre-charges and the battery charge current limit (Ichg _ lim) is set equal to the constant current limit (Ilim _ cc). The pre-charge is performed using a step-down charger until the battery charge voltage (Vbat) exceeds a first voltage threshold (Vlow), which may also be referred to as a pre-charge voltage threshold. State 606 corresponds to a constant current buck phase in which the battery charging current (Ichg) remains constant and the battery charging voltage (Vbat) is gradually increased. When the battery charge voltage (Vbat) exceeds the second voltage threshold (Vsc _ min) but is below the third voltage threshold (Vcv _ buck), then the buck charger is disabled, the open loop charger 350 (e.g., a switched capacitor charger) is enabled, and state 608 occurs. State 608 corresponds to a switched capacitor constant current phase in which the battery 152 is charged using a switched capacitor charger while maintaining the battery charging current (Ichg) substantially constant until the battery charging voltage (Vbat) reaches another voltage threshold (Vcv _ sc), at which time the state transitions to state 610. State 610 corresponds to a constant voltage switched capacitor state in which the battery is charged using the switched capacitor charger while maintaining the battery charge voltage (Vbat) substantially constant until the battery charge current (Ichg) falls below the first current threshold (Isc _ min), at which time the switched capacitor charger is disabled, the buck charger is enabled, and the state transitions to state 612. As shown in fig. 6, a direct transition from state 612 to state 606 is also possible if the battery charge voltage (Vbat) exceeds the third voltage threshold (Vcv _ buck). This may occur, for example, when the battery is already near full charge at the beginning of charging.

State 612 corresponds to a constant voltage buck phase in which the battery is charged using the buck charger while maintaining the battery charge voltage (Vbat) substantially constant until the battery charge current (Ichg) falls below the second current threshold (Iterm), at which point the buck charger is disabled and charging stops at state 614 because the battery is fully charged.

In the above description, Ilim is the current limit setting for pre-charging, with an example value of 120 mA. Ilim _ CC is a current limit setting for CC buck charging, with example values of 1A-2A. Iterm is the end current setting, with an example value of 10 mA. Vcv _ SC is the minimum voltage into the CV SC, with an example value of 4.1V. Vcv _ buck is the minimum voltage to go into the CV buck, with an exemplary value of 4.2V.

In some embodiments, the PR controller 344 is used to control the system 300 when the open loop DC-DC converter 350 is used to charge the battery 152. When the open-loop DC-DC converter 350 is operating, the PR controller 344 controls the entire wireless battery charging system to operate in the closed-loop mode. In some embodiments, the PR controller 344 adjusts Ichg (for CC SC state) or the charging voltage (for CV SC state). In the constant current charging state, the PR controller 344 adjusts the charging current to follow the target value. In the constant voltage charging state, the PR controller 344 adjusts the battery charging voltage to follow the target value.

In one embodiment, the PR controller 344 regulates a voltage (Vin) at an input of the wireless power TXIC226 and a voltage (Vbus) at an output of the wireless power RXIC246 to achieve one or more purposes. One purpose is to regulate the charging current (for the CC SC state) or the charging voltage (for the CV SC state). Another purpose is to control the gain (Vbus/Vin) between the output of the RXIC246 and the input of the TXIC226 to be close to a particular value that supports coupling and loading condition changes. Yet another object may be to control the operating frequency of the wireless charging system to be at or near a particular value that supports coupling and loading condition variations. Control of Vbus may be through communication internal to the charger 342, e.g., by the PR controller 344 sending commands to the RXIC to alter its output reference. Control of Vin (at the input of the radio power TXIC 226) may be performed by: the PR controller 344 sends commands to the RXIC246 to transfer information to the TXIC226 using the receive coil L2. If communication between the radio energy RXIC246 and the radio energy TXIC226 is affected, control of the open loop DC to DC converter 350 may also be affected.

Fig. 7 is a diagram of a system 700 for charging the battery 152. System 700 includes a wireless power RX connected to battery 152 and load 162 and charger 342. The wireless power RXIC246 of the wireless power RX and charger 342 wirelessly receives power from the wireless power TXIC 226. The wireless power RX and charger 342 is similar to the system 300 of fig. 3, however, when the open loop DC-DC converter 350 is being used to charge the battery 152, the wireless power RX and charger 342 does not have a linear regulator 360 to reduce or eliminate interference from the load 162 when wirelessly communicating to the wireless power TXIC226 using the receive coil L2. To simplify the figure, the wireless power TX122 in fig. 3 has been simplified to depict only the wireless power TXIC226, C1, and L1. The system 700 may have other elements shown in fig. 3, such as the PD controller 224, the half-bridge inverter 228, and/or the adapter 112.

Fig. 8A-8C are graphs of various waveforms illustrating how load 162 may interfere with communications in system 700 of fig. 7 when open loop DC-DC converter 350 is used to charge battery 152. In particular, the transient current drawn by the load 162 may interfere with communications using the receive coil L2 to communicate information to the wireless power TXIC 226. These waveforms are applicable to a variety of currents and voltages when the open loop DC-DC converter 350 is being used to charge the battery 152. The horizontal axis of each of fig. 8A to 8C represents time. The time axes are aligned with each other and cover the same time period. In this example, the time unit is milliseconds. The vertical axis in fig. 8A represents the current of waveform 802. The vertical axis in fig. 8B represents the voltage of waveforms 804 and 806. The vertical axis in fig. 8C represents the current of waveforms 810 and 812.

Waveform 802 in fig. 8A represents the current drawn by load 162 (Iload). Before time 2.0 (milliseconds), the load current is stable. Thus, the load current is not transient in nature until time 2.0 (milliseconds), and does not interfere with communications using the receive coil L2. In this example, the load current is periodic with a frequency of about 2000Hz after time 2.0 (milliseconds). That is, the amount of current drawn by the load 162 is periodically varied. Thus, after time 2.0 (milliseconds), the load current is transient in nature because it has one or more transient changes in current intensity. Note that the load current may be provided by the open loop DC-DC converter 350 and/or the battery 152.

Waveform 810 in fig. 8C represents the current (Ichg) provided by the output of open loop DC-DC converter 350. The waveform 812 in fig. 8C represents the current (Ibus) on the power bus 354 at the output of the wireless power RXIC 246. In fig. 7, the power bus 354 connects the output of the wireless power RXIC246 to the input of the open loop DC-DC converter 350 such that the current at the input of the open loop DC-DC converter 350 is the same as the current (Ibus) on the power bus 354 at the output of the wireless power RXIC 246. Note that this assumption is based on the following case: the open-loop DC-DC converter 350 is operated without enabling the closed-loop DC-DC converter 348, and thus no current is input from or output to the power bus 354. Also assume in this figure that open-loop DC-DC converter 350 is a switched capacitor charger with a 2:1 buck conversion ratio, such that the value of Ibus (as shown by waveform 812) is about half the value of Ichg (as shown by waveform 810). Note that during steady state (2ms before), the value of Iload (as shown by waveform 802) is lower than the value of Ichg (as shown by waveform 810). This indicates that an excessive current is flowing into the battery 152 and the battery is charging. After 2ms, when Iload (as shown in waveform 802) exhibits a high transient current, the value of Iload is higher than the value of Ichg (as shown in waveform 810). This is because the battery 152 is no longer charged at this time. In contrast, battery 152 is discharging and supplementing the additional current required by load 162 (as shown by waveform 802), which the current provided by open-loop DC-DC converter 350 (Ichg) cannot provide.

Waveform 804 in fig. 8B represents the voltage at terminal 352 connected to battery 152 (Vbat). In fig. 7, the voltage at terminal 352 connected to battery 152 is the same as the voltage at the output (Vbat) of open loop DC-DC converter 350. Waveform 806 in fig. 8C represents the voltage (Vbus) on the power bus 354 at the output of the wireless power RXIC 246. In fig. 7, the voltage at the input of the open loop DC-DC converter 350 is the same as the voltage (Vbus) output by the wireless power RXIC246 to the power bus 354. Assume also in this figure that open-loop DC-DC converter 350 is a switched capacitor charger with a 2:1 buck conversion ratio such that the value of voltage Vbus (as shown by waveform 806) is approximately twice the value of voltage Vbat (as shown by waveform 804). During steady state (before 2 ms), Vbat is maintained at a level such that open loop DC-DC converter 350 provides a steady current to charge the battery. When a load transient occurs at 2ms and periodically thereafter, it is noted that the battery voltage Vbat (as shown by waveform 804) falls periodically. Thus, Vbat falls periodically compared to the value before 2ms (when no load transient occurs). This is because the battery 152 is now discharging and supplementing the extra current required by the load (Iload), which the open-loop DC-DC converter 350 provides (Ichg) cannot provide. As the battery 152 discharges, the voltage at the battery terminals decreases.

When the battery is charging (i.e., no transient load current), the voltage drop caused by the internal resistance of the battery may increase above the cell voltage. Conversely, when the battery is discharging (i.e., when there is a transient load current), the voltage drop caused by the internal resistance of the battery may be subtracted from the cell voltage. The net effect is that the battery voltage may oscillate with the transient load current (see waveform 804). This oscillation of the battery voltage may be sufficient to cause a sudden change in current from the open loop DC-DC converter 350, as such current may depend on the voltage difference between the output of the wireless power RXIC246 and the battery voltage.

Thus, waveforms 804 and 810 indicate that the voltage and current at the output of open loop DC-DC converter 350 both vary with load current transitions, and with battery voltage (Vbat) transitions caused by load current transitions. Since the DC-DC converter 350 operates in an open loop, voltage and current changes at its output (Vbat) will result in voltage and current changes at its input (Vbus). Thus, as the voltage at the output of the open-loop DC-DC converter 350 (shown as waveform 804) rises and falls, the voltage at the input of the open-loop DC-DC converter 350 (shown as waveform 806) also rises and falls. Similarly, as the current at the output of the open-loop DC-DC converter 350 (shown as waveform 810) rises and falls, the current at the input of the open-loop DC-DC converter 350 (shown as waveform 812) also rises and falls.

Referring now to fig. 7, as the voltage at the input of the open loop DC-DC converter 350 rises and falls, the voltage (Vbus) on the power bus 354 at the output of the wireless power RXIC also rises and falls. Similarly, as the current at the input of the open loop DC-DC converter 350 rises and falls, the current in the power bus 354 at the output of the wireless power RXIC (Ibus) also rises and falls. Such a change in the voltage and/or current at the output of the wireless power RXIC246 causes a change in the current through the receive coil L2, thereby causing a change in the current Ip in the coil L1 of the wireless power TXIC 226. Communication from the radio energy RXIC246 to the radio energy TXIC226 is dependent upon the radio energy TXIC226 detecting small changes in the current Ip in the coil L1. Therefore, a change in the current Ip due to the transient load current may disturb communication.

Embodiments disclosed herein may reduce the variation of Vbus and Ibus during load transients, thereby mitigating wireless communication interference issues. In one embodiment, as shown in FIG. 3, a regulator 360 is inserted into the power bus 354. The regulator 360 increases its internal resistance in response to load current transients to create a voltage drop between the output of the wireless power RXIC246 and the input of the open loop DC-DC converter 350, thereby stabilizing the voltage at the output of the wireless power RXIC 246. This effectively limits the variation in voltage Vbus and current Ibus on power bus 354a to a level sufficient to reduce communication interference. In another embodiment, as shown in fig. 10A, a regulator 360 is interposed between the output of the open-loop DC-DC converter 350 and the battery 152. The regulator 360 increases its internal resistance in response to load current transients to create a voltage drop between the output of the open-loop DC-DC converter 350 and the battery 152, thereby stabilizing the voltage at the output of the open-loop DC-DC converter 350. This essentially forces the battery 152 to be the primary source of load transient current. This mechanism, in turn, stabilizes Vbus and Ibus on the power bus 354 at the output of the wireless power RXIC246 to a degree sufficient to reduce wireless communication interference.

Fig. 9A and 9B are graphs showing how transient current drawn by the load 162 may affect wireless communication when using the receive coil L2 of fig. 7. Fig. 9A depicts packet failure rate (vertical axis) versus load current frequency (horizontal axis). The packet refers to a packet of information transmitted from the radio power RXIC246 to the radio power TXIC226 using the Qi standard or the like. Line 902 represents the packet failure rate. The line 904 represents the approximate frequency of wireless communication from the radio power RXIC246 to the radio power TXIC 226. In this example, the packet failure rate is highest when the frequency of the transient current is close to the frequency of the wireless communication.

Embodiments disclosed herein may reduce the packet failure rate, including reducing the packet failure rate to zero. In one embodiment, the current regulator 360 is used to stabilize Ibus in the power bus 354 at the output of the wireless power RXIC246 to a degree sufficient to reduce the packet failure rate. In one embodiment, a current regulator 360 is used to stabilize Vbus on the power bus 354 at the output of the wireless power RXIC246 to a degree sufficient to reduce the packet failure rate. In one embodiment, current regulators 360 are used to stabilize both Ibus and Vbus at the output of the wireless power RXIC246 to a degree sufficient to reduce the packet failure rate.

Fig. 9B depicts the complete communication failure rate (vertical axis) versus load current frequency (horizontal axis). For example, the load disturbance may be very severe and even remedial measures such as resending failed packets may fail to provide communication. Line 906 represents the complete communication failure rate. The line 904 still represents the approximate frequency of wireless communication from the radio power RXIC246 to the radio power TXIC 226. In this example, the full communication failure rate is highest when the frequency of the transient current is close to the frequency of the wireless communication. Embodiments disclosed herein may reduce the rate of complete communication failure, including reducing the rate of complete communication failure to zero.

Fig. 10A-10C are diagrams of various embodiments of a wireless power RX and charger 342 with a linear regulator 360. The linear regulator 360 may be used to reduce interference caused by transient currents drawn by the load 162 connected to the wireless power RX and the charger 342. Therefore, wireless communication using the receiving coil L2 can be improved. The wireless power RX and charger 342 operates in a similar manner as described in connection with the wireless power RX and charger 342 of fig. 3, except for the position of the linear regulator 360. To simplify the drawing, some components of the adapter 112 and the wireless power TX122 are not depicted in fig. 10A-10C.

Referring now to fig. 10A, the wireless power RX and charger 342 has a wireless power RXIC246, a closed loop DC-DC converter 348, an open loop DC-DC converter 350, and a linear regulator 360. In one embodiment, linear regulator 360 is used to limit the current so that the current does not exceed a target level. For example, when using the open-loop DC-DC converter 350, the linear regulator 360 may be used to limit Ichg such that Ichg does not exceed the target current for charging the battery 152.

The output (Vout) of the linear regulator 360 provides Ichg to the battery 152 when the open-loop DC-DC converter 350 is being used to charge the battery 152. The load 162 may draw a portion of Ichg. Note that the PR controller 344 controls the components in the wireless power RX and charger 342 so that the open-loop DC-DC converter 350 provides current to the linear regulator 360 (when the open-loop DC-DC converter 350 is being used to charge the battery 152). Assuming that the linear regulator 360 does not actively regulate the current through the linear regulator 360, the magnitude of the current provided to the linear regulator 360 is determined by the load current Iload and the battery voltage Vbat. When the load current is small, Ichg provides both load current Iload and battery charging current. When load 162 draws a large load current causing Iload to exceed Ichg, the battery switches its effect from charging to discharging and supplements Ichg in providing load current Iload. In this process, the battery voltage Vbat decreases as the battery action changes, so that a large voltage difference is generated between the output of the wireless power RXIC246 and the battery voltage. Due to the nature of the open loop circuit, a larger voltage difference naturally results in a higher Ichg.

In one embodiment, the closed-loop DC-DC converter 348 is inactive when the open-loop DC-DC converter 350 is being used to charge the battery 152, so the closed-loop DC-DC converter 348 does not provide any Ichg at the time. However, when the closed-loop DC-DC converter 348 is being used to charge the battery 152, the closed-loop DC-DC converter 348 provides Ichg.

The linear regulator 360 is connected along a power path from the output of the radio power RX to the terminal 352 connected to the ungrounded side of the battery 152. A portion of this power path extends from the input of the open-loop DC-DC converter 350 to the output of the open-loop DC-DC converter 350. It can also be said that the linear regulator 360 is coupled in series with the open-loop DC-DC converter 350. In fig. 10A, the input (Vin) of the linear regulator 360 is connected to the output (Vbat) of the open-loop DC-DC converter 350 to receive current from the open-loop DC-DC converter 350. Note that in some embodiments, the open loop DC-DC converter 350 may increase the current. Thus, the magnitude of the current at the output (Vbat) of the open-loop DC-DC converter 350 may be different from the magnitude of the current at the output (Vout) of the linear regulator 360.

In one embodiment, linear regulator 360 has a first mode in which it actively regulates current in linear regulator 360 and a second mode in which it does not actively regulate current in linear regulator 360. When the linear regulator 360 is not actively regulating current, the voltage drop (between Vin and Vout) of the linear regulator 360 is very close to zero and the resistance from the input (Vin) to the output (Vout) of the linear regulator 360 is very low. In one embodiment, to regulate current, the voltage drop increases and the resistance from the input (Vin) to the output (Vout) increases.

The PR controller 344 controls the linear regulator 360 to stabilize Ibus in the power bus 354 at the output of the wireless power RXIC246 and/or Vbus on the power bus at the output of the wireless power RXIC 246. Stabilizing Ibus and/or Vbus at the output of the wireless power RXIC246 may reduce load disturbances when wireless communication from the wireless power RXIC246 to the wireless power TXIC226 is conducted using the receive coil L2 while the open loop DC-DC converter 350 is being used to charge the battery 152.

In one embodiment, the linear regulator 360 stabilizes the current and/or voltage at its input (Vin), thereby stabilizing the current and/or voltage at the output (Vbat) of the open-loop DC-DC converter 350. If the current and/or voltage at the output (Vbat) of the open-loop DC-DC converter 350 is not stable, the current and/or voltage at the input (Vbus) of the open-loop DC-DC converter 350 may not be stable. Accordingly, Ibus and/or Vbus on the power bus 354 at the output of the wireless power RXIC246 may be unstable, which may interfere with wireless communications using the receive coil L2. However, when the linear regulator 360 stabilizes the current and/or voltage at its input (Vin), the net effect is to stabilize Ibus and/or Vbus on the power bus 354 at the output of the wireless power RXIC 246. In one embodiment, the linear regulator 360 stabilizes both the current and voltage at its input (Vin), the net effect being to stabilize Ibus and Vbus on the power bus 354 at the output of the wireless power RXIC 246.

Fig. 10B and 10C illustrate other locations of the linear regulator 360 in the wireless power RX and charger 342. Fig. 10B illustrates an embodiment in which the input (Vin) of the linear regulator 360 is connected to both the outputs of the closed-loop DC-DC converter 348 and the open-loop DC-DC converter 350. The output (Vout) of the linear regulator 360 provides Ichg to the battery 152 when the open-loop DC-DC converter 350 is being used to charge the battery 152. The load 162 may draw a portion of Ichg. The operation of the linear regulator 360 of fig. 10B may be similar to the embodiment of fig. 10A and therefore will not be described again. When the closed loop DC-DC converter 348 is being used to charge the battery 152, no active regulation using the linear regulator 360 is required.

Fig. 10C illustrates an embodiment in which the output (Vout) of the linear regulator 360 is connected to both the inputs of the closed-loop DC-DC converter 348 and the open-loop DC-DC converter 350. The input (Vin) of the linear regulator 360 has Vbus from the output of the wireless power RXIC 246. The operation of the linear regulator 360 of fig. 10C may be similar to the embodiment of fig. 3 and therefore will not be described again. When the closed loop DC-DC converter 348 is being used to charge the battery 152, no active regulation using the linear regulator 360 is required.

In the various embodiments of fig. 3, 10A, 10B, and 10C, two or more of the linear regulator 360, the open-loop DC-DC converter 350, and the closed-loop DC-DC converter 348 may be integrated in the same semiconductor package. In one embodiment, the linear regulator 360 and the open-loop DC-DC converter 350 are integrated in the same semiconductor package, while the closed-loop DC-DC converter 348 is in a separate package. In one embodiment, all three of the linear regulator 360, the open-loop DC-DC converter 350, and the closed-loop DC-DC converter 348 are integrated in the same semiconductor package.

Fig. 11A is a flow diagram of one embodiment of a process 1100 of operating the wireless power RX and charger 342. Process 1100 may be used in any of wireless power RX and charger 342 of fig. 3, 10A-10C, but is not so limited. Step 1102 includes wirelessly receiving power at the wireless power RXIC246 using the receive coil L2. In one embodiment, the power is from the wireless power TXIC 226. In one embodiment, the received power is AC power.

In one embodiment, step 1104 includes the wireless power RXIC246 outputting power to the power bus 354 based on wirelessly received power. In one embodiment, the power on the power bus 354 is DC power. In one embodiment, the wireless power RXIC246 outputs Ibus and Vbus to the power bus 354 based on wirelessly received power.

Step 1106 includes using the receive coil L2 for wireless communication from the wireless power RXIC246 to a transmitter of power. In one embodiment, the radio power RXIC246 communicates with the radio power TXIC226 using the receive coil L2. In one embodiment, the communication is performed according to the Qi standard.

Step 1108 includes enabling the open-loop DC-DC converter 350 to charge the battery 152 using power on the power bus 354. Step 1108 may include operating open-loop DC-DC converter 350 in a constant current phase and/or a constant voltage phase. For example, step 1108 may include operating open-loop DC-DC converter 350 between times T2 and T4 in fig. 5. In one embodiment, step 1108 includes operating open-loop DC-DC converter 350 at state 608 and/or state 610 in fig. 6.

Step 1110 includes controlling the linear regulator 360 to reduce load disturbances when the receive coil L2 is used for communication from the radio power RXIC246 to a transmitter of power (e.g., the radio power TXIC 226). In one embodiment, step 1110 includes controlling the linear regulator 360 to stabilize the current (Ibus) in the power bus 354 at the output of the wireless power RXIC 246. In one embodiment, step 1110 includes controlling the linear regulator 360 to stabilize the voltage (Vbus) on the power bus 354 at the output of the wireless power RXIC 246. In one embodiment, step 1110 includes controlling the linear regulator 360 to simultaneously stabilize Ibus and Vbus at the output of the wireless power RXIC 246. Step 1110 is performed when the open-loop DC-DC converter 350 is enabled to charge the battery 152 with wirelessly received power. In one embodiment, the load disturbance originates from a transient current of the load 162. The transient current may be periodic as illustrated by waveform 802 in fig. 8A. The frequency of the transient current may be close to the frequency of the wireless communication in step 1106, but this is not required.

Fig. 11B is a flow diagram of one embodiment of a process 1150 of operating the wireless power RX and charger 342. Process 1150 may be used in any of wireless power RX and charger 342 of fig. 3, 10A-10C, but is not limited to such. Step 1152 includes wirelessly receiving power at the wireless power RXIC246 using the receive coil L2. In one embodiment, the power is from the wireless power TXIC 226. In one embodiment, the received power is AC power.

In one embodiment, step 1154 includes the wireless power RXIC246 outputting power to the power bus 354 based on wirelessly received power. In one embodiment, the power on the power bus 354 is DC power. In one embodiment, the wireless power RXIC246 outputs Ibus and Vbus to the power bus 354 based on wirelessly received power.

Step 1156 includes using the receive coil L2 for wireless communication from the wireless power RXIC246 to a transmitter of power. In one embodiment, the radio power RXIC246 communicates with the radio power TXIC226 using the receive coil L2. In one embodiment, the communication is performed according to the Qi standard.

Step 1158 includes selectively enabling one of the closed loop DC-DC converter 348 and the open loop DC-DC converter 350 each time the battery 152 is charged using power output by the wireless power RXIC246 to the power bus 354.

Step 1158 may include operating the closed-loop DC-DC converter 348 in a constant current phase and/or a constant voltage phase. For example, step 1158 may include operating closed-loop DC-DC converter 348 between times T1 and T2 and times T4 and T5 in fig. 5. In one embodiment, step 1156 includes operating closed loop DC-DC converter 348 at state 606 and/or state 612 in fig. 6. Step 1156 may also include operating the closed loop DC-DC converter 348 during the precharge phase, such as state 604 of fig. 6.

Step 1158 may include operating the open-loop DC-DC converter 350 in a constant current phase and/or a constant voltage phase. For example, step 1158 may include operating open-loop DC-DC converter 350 between times T2 and T4 in fig. 5. In one embodiment, step 1158 includes operating open-loop DC-DC converter 350 at state 608 and/or state 610 in fig. 6.

Step 1160 includes controlling a linear regulator 360 coupled in series with the open loop DC-DC converter 350 to reduce load disturbances when wireless communication is made from the wireless power RXIC246 to a transmitter of power using the receive coil L2. In one embodiment, step 1160 includes controlling the linear regulator 360 to stabilize a current (Ibus) on the power bus 354 at the output of the wireless power RXIC 246. In one embodiment, step 1160 includes controlling the linear regulator 360 to stabilize the voltage (Vbus) on the power bus 354 at the output of the wireless power RXIC 246. In one embodiment, step 1160 includes controlling the linear regulator 360 to simultaneously stabilize Ibus and Vbus at the output of the wireless power RXIC 246. Step 1160 is performed when the open-loop DC-DC converter 350 is enabled to charge the battery 152 with wirelessly received power. In one embodiment, the load disturbance originates from a transient current of the load 162. The transient current may be periodic as illustrated by waveform 802 in fig. 8A. The frequency of the transient current may be close to the frequency of the wireless communication in step 1104, but this is not required.

In one embodiment, when the open loop DC-DC converter 350 is being used to charge the battery 152, the PR controller 344 is used to operate the linear regulator 360 in the following mode: the linear regulator 360 does not actively limit current in the linear regulator 360 unless the load 162 draws a transient current. FIG. 12A is a graph depicting one embodiment of operating the linear regulator 360 in this mode. The graph shows current versus time. The time frame includes the beginning of the constant current phase of operation of the open loop controller 350. For example, the time range in FIG. 12A may correspond to an extension of about T2 in FIG. 5, showing the gradual rise in waveform 506 from 1A to about 4A. Of course, these principles may also be applied to other times (and situations) when the open-loop controller 350 is operated to charge the battery 152.

Waveform 1202 represents Ichg under the assumption that there is no dynamic load. In other words, load 162 draws no transient current for waveform 1202. In one embodiment, the step-up of waveform 1202 corresponds to waveform 506 (see FIG. 5) gradually rising from 1A to about 4A at time T2. In one embodiment, note that Ichg is the target current for charging battery 152.

Waveform 1204 represents the threshold current magnitude at which the linear regulator 360 enters the active regulation mode. Waveform 1204 remains slightly higher than waveform 1202, meaning that linear regulator 360 is not in the active regulation mode if load 162 has no transient current. However, if load 162 has a transient current, linear regulator 360 may enter an active regulation mode in which linear regulator 360 regulates the current in linear regulator 360. Specifically, linear regulator 360 may limit its internal current so that it does not exceed the amplitude of waveform 1204.

In one embodiment, the PR controller 344 provides a signal to the linear regulator 360 to determine the threshold current magnitude. Thus, in one embodiment, the PR controller 344 is configured to operate the linear regulator 360 in a mode where the linear regulator threshold current limit is slightly higher than the target battery charging current. Thus, the linear regulator 360 will not actively regulate current when there is no transient load current. Therefore, the resistance of the linear regulator 360 may be very low. In addition, the voltage drop of the linear regulator 360 may also be very low. Thus, any power loss caused by the linear regulator 360 may be very low.

In one embodiment, when the open loop DC-DC converter 350 is being used to charge the battery 152, the PR controller 344 is used to operate the linear regulator 360 in the following mode: the linear regulator 360 actively limits current in the linear regulator 360 regardless of whether the load 162 is drawing transient current. Fig. 12B is a graph of voltage versus time for linear regulator 360 to illustrate this mode. The graph shows voltage versus time. The time frame encompasses the beginning of the constant current phase of operation of the open-loop controller 350, as shown in the graph of fig. 12A. Of course, these principles may also be applied to other times (and situations) when the open-loop controller 350 is operated to charge the battery 152.

Waveform 1222 represents an estimated voltage (Vbus) that is determined at the output of the radio power RXIC246 in order for the open loop DC-DC converter 350 to provide the required current for the battery 152. Waveform 1222 assumes no dynamic loading and ignores linear regulator 360.

Waveform 1224 is the actual target voltage (Vbus) that is determined at the output of the wireless power RXIC246 to both meet the charge current target and operate the linear regulator 360 in the active regulation mode. Waveform 1224 is about 50-100 millivolts greater than waveform 1222. However, this difference may be less than 50 millivolts or greater than 100 millivolts.

This estimated voltage (Vbus) of waveform 1222 may be determined based on factors such as: a gain or equivalent series resistance of the open-loop DC-DC converter 350, a target voltage at the top terminal of the battery 152, a target current (Ibus) at the output of the wireless power RXIC246, and an equivalent impedance between the output of the wireless power RXIC246 and the top terminal of the battery 152.

In one embodiment, the linear regulator 360 also provides reverse current protection or Reverse Blocking (RB). Fig. 13A depicts one embodiment in which wireless power RX and charger 342 has a linear regulator/RB 1310, linear regulator/RB 1310 providing reverse current protection in addition to being a linear regulator 360, as described herein. In one embodiment, linear regulator/RB 1310 includes a MOSFET that operates in the linear region to act as a linear regulator. The configuration in fig. 13A is similar to the configuration in fig. 10C in that the linear regulator output (Vout) is connected to the inputs of both the closed-loop DC-DC converter 348 and the open-loop DC-DC converter 350. In another option, the linear regulator/RB is connected to the input of the open-loop DC-DC converter 350 instead of the input of the closed-loop DC-DC converter 348.

In one embodiment, the linear regulator 360 also provides over-voltage protection (OVP). Fig. 13B depicts one embodiment in which the wireless power RX and charger 342 has a linear regulator/OVP 1320, the linear regulator/OVP 1320 providing OVP in addition to being the linear regulator 360, as described herein. In one embodiment, the linear regulator/OVP 1320 comprises a MOSFET operating in the linear region to act as a linear regulator. The configuration in fig. 13B is similar to the configuration in fig. 10C in that the linear regulator output (Vout) is connected to the inputs of both the closed-loop DC-DC converter 348 and the open-loop DC-DC converter 350. In another option, the linear regulator/OVP 1320 is connected to the input of the open-loop DC-DC converter 350 instead of the input of the closed-loop DC-DC converter 348.

Certain embodiments of the techniques described herein may be implemented using hardware, software, or a combination of hardware and software. The software is stored on one or more of the processor-readable storage devices described above to program one or more of the processors to perform the functions described herein. The processor-readable storage device may include computer-readable media, such as volatile and non-volatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer readable storage media and communication media. Computer-readable storage media may be implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. Examples of computer readable storage media include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. A computer-readable medium does not include propagated, modulated, or transitory signals.

Communication media typically embodies computer readable instructions, data structures, program modules or other data in a propagated, modulated or transitory data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term "modulated data signal" means a signal that: one or more characteristics of a signal may be set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as RF and other wireless media. Combinations of any of the above are also included within the scope of computer readable media.

In alternative embodiments, some or all of the software may be replaced with dedicated hardware logic components. By way of example, and not limitation, exemplary types of hardware Logic components that may be used include Field-Programmable gate arrays (FPGAs), Application-specific Integrated circuits (ASICs), Application-specific Standard products (ASSPs), System-on-a-chips (SOCs), Complex Programmable Logic Devices (CPLDs), special purpose computers, and the like. In one embodiment, the one or more processors are programmed with software (stored on a storage device) to implement one or more embodiments. The one or more processors may communicate with one or more computer-readable media/storage devices, peripherals, and/or communication interfaces.

It should be understood that the present subject matter may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this subject matter will be thorough and complete, and will fully convey the invention to those skilled in the art. Indeed, the present subject matter is intended to cover alternatives, modifications and equivalents of these embodiments, which are included within the scope and spirit of the present subject matter as defined by the appended claims. Furthermore, in the following detailed description of the present subject matter, numerous specific details are set forth in order to provide a thorough understanding of the present subject matter. However, it will be apparent to one of ordinary skill in the art that the claimed subject matter may be practiced without such specific details.

Aspects of the present invention are described herein in connection with flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable instruction execution apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.