阅读说明：本技术 混合功率转换器 (Hybrid power converter ) 是由 陈俊晓 黄金彪 李锃 于 2018-11-16 设计创作，主要内容包括：本发明涉及混合功率转换器技术领域,具体公开了一种混合转换器设备的运行方法,包括响应于混合转换器的输入电压大于第一阈值,将混合转换器配置为在包括四个运行阶段的混合模式下运行,响应于混合转换器的所述输入电压小于第二阈值,将混合转换器配置为在包括两个运行阶段的降压模式下运行,以及响应于混合转换器的输入电压小于第一阈值并且大于第二阈值,将混合转换器配置为在包括两个运行阶段的电荷泵模式下运行。(The invention relates to the technical field of hybrid power converters, and particularly discloses an operation method of a hybrid converter device.)

1. A method of operating a hybrid converter apparatus, comprising:

in response to an input voltage of a hybrid converter being greater than a first threshold, configuring the hybrid converter to operate in a hybrid mode comprising four operating phases;

in response to the input voltage of the hybrid converter being less than a second threshold, configuring the hybrid converter to operate in a buck mode comprising two phases of operation; and

in response to the input voltage of the hybrid converter being less than the first threshold and greater than the second threshold, configuring the hybrid converter to operate in a charge pump mode comprising two phases of operation.

2. The method of claim 1, wherein the hybrid converter comprises:

a first switch, a capacitor, and a second switch, the first switch, the capacitor, and the second switch connected in series between an output of a voltage source and an inductive-capacitive filter;

a third switch connected between a common node of the first switch and the capacitor and a common node of the second switch and the LC filter; and

a fourth switch connected between a common node of the capacitor and the second switch and ground.

3. The method of claim 2, wherein the configuring the hybrid converter to operate in the hybrid mode comprises:

in a first phase of the hybrid mode, the first switch and the second switch are configured to be closed and the third switch and the fourth switch are configured to be open;

in a second phase of the hybrid mode, the second switch and the fourth switch are configured to be closed, and the first switch and the third switch are configured to be open;

in a third phase of the hybrid mode, the third switch and the fourth switch are configured to be closed, and the first switch and the second switch are configured to be open; and is

In a fourth phase of the hybrid mode, the second switch and the fourth switch are configured to be closed, and the first switch and the third switch are configured to be open.

4. The method of claim 3, wherein the configuring the hybrid converter to operate in the charge pump mode comprises:

in a first phase of the charge pump mode, the first switch and the second switch are configured to be closed, and the third switch and the fourth switch are configured to be open; and

in a second phase of the charge pump mode, the third switch and the fourth switch are configured to be closed, and the first switch and the second switch are configured to be open.

5. The method of claim 4,

in response to a mode switch from the hybrid mode to the charge pump mode, the hybrid converter exits at the end of the fourth phase of the hybrid mode and enters the first phase of the charge pump mode; and

in response to a mode switch from the charge pump mode to the hybrid mode, the hybrid converter exits at the end of the second phase of the charge pump mode and enters the first phase of the hybrid mode.

6. The method of claim 4, wherein the configuring the hybrid converter to operate in the buck mode comprises:

in a first phase of the buck mode, configuring the first switch and the third switch to be closed and the second switch and the fourth switch to be open; and

in a second phase of the buck mode, the second switch and the fourth switch are configured to be closed and the first switch and the third switch are configured to be open.

7. The method of claim 6,

in response to a mode switch from the charge pump mode to the buck mode, the hybrid converter exits at the end of the second phase of the charge pump mode and enters the first phase of the buck mode; and

in response to a mode switch from the buck mode to the charge pump mode, the hybrid converter exits at the end of the second phase of the buck mode and enters the first phase of the charge pump mode.

8. The method of claim 6,

in the buck mode, the capacitor is floating.

9. The method of claim 6,

in the buck mode, the capacitor is precharged to a voltage level approximately equal to twice an output voltage of the hybrid converter.

10. The method of claim 9,

precharging the capacitor to the voltage level to enable smooth switching between the buck mode and the charge pump mode.

11. The method of claim 1,

the first threshold is approximately equal to twice an output voltage of the hybrid converter plus a hysteresis voltage; and is

The second threshold is approximately equal to twice the output voltage of the hybrid converter minus the hysteresis voltage.

12. The method of claim 11,

the hysteresis voltage is about 5% of the output voltage of the hybrid converter.

13. A method of operating a hybrid converter apparatus, comprising:

detecting an input voltage and an output voltage of a power system including the hybrid converter;

configuring the hybrid converter to operate in a hybrid mode comprising four operating phases when an input voltage of the hybrid converter is greater than a first threshold;

configuring the hybrid converter to operate in a buck mode comprising two operating phases when the input voltage of the hybrid converter is less than a second threshold; and

configuring the hybrid converter to operate in a charge pump mode comprising two operating phases when the input voltage of the hybrid converter is between the first threshold and the second threshold.

14. The method of claim 13, wherein the power system is a wireless power transfer system, the power system comprising:

a transmitter switching network coupled to an input power supply;

a transmitter coil coupled to the transmitter switching network;

a receiver coil configured to be magnetically coupled to the transmitter coil;

a rectifier connected to the receiver coil; and

the hybrid converter is connected between the rectifier and a load.

15. The method of claim 13,

a first switch, a capacitor and a second switch, the first switch, the capacitor and the second switch being connected in series between an output of a voltage source and an output filter;

a third switch connected between a common node of the first switch and the capacitor and a common node of the second switch and the output filter; and

a fourth switch connected between a common node of the capacitor and the second switch and ground.

16. The method of claim 15, wherein the configuring the hybrid converter to operate in the hybrid mode comprises:

in a first phase of the hybrid mode, the first switch and the second switch are configured to be closed and the third switch and the fourth switch are configured to be open;

in a second phase of the hybrid mode, the second switch and the fourth switch are configured to be closed, and the first switch and the third switch are configured to be open;

in a third phase of the hybrid mode, the third switch and the fourth switch are configured to be closed, and the first switch and the second switch are configured to be open; and is

In a fourth phase of the hybrid mode, the second switch and the fourth switch are configured to be closed, and the first switch and the third switch are configured to be open.

17. The method of claim 15, wherein the configuring the hybrid converter to operate in the charge pump mode comprises:

in a first phase of the charge pump mode, configuring the first switch and the second switch to be closed and the third switch and the fourth switch to be open; and

in a second phase of the charge pump mode, the third switch and the fourth switch are configured to be closed and the first switch and the second switch are configured to be open.

18. The method of claim 15, wherein the configuring the hybrid converter to operate in the buck mode comprises:

in a first phase of the buck mode, configuring the first switch and the third switch to be closed and the second switch and the fourth switch to be open; and

in a second phase of the buck mode, the second switch and the fourth switch are configured to be closed and the first switch and the third switch are configured to be open.

19. The method of claim 15, wherein the configuring the hybrid converter to operate in the buck mode comprises:

in a first phase of the buck mode, configuring the first switch, the second switch, and the third switch to be closed and the fourth switch to be open; and

in a second phase of the buck mode, the second switch, the third switch, and the fourth switch are configured to be closed and the first switch is configured to be open.

20. The method of claim 13,

the first threshold is approximately equal to twice an output voltage of the hybrid converter plus a hysteresis voltage; and is

The second threshold is approximately equal to twice the output voltage of the hybrid converter minus the hysteresis voltage.

Technical Field

The present invention relates to hybrid power converters, and in particular embodiments, to hybrid power converters in receivers of wireless power transfer systems.

Background

As technology further advances, wireless power transfer has emerged as an efficient and convenient mechanism for powering or charging battery-based mobile devices, such as mobile phones, tablet PCs, digital cameras, MP3 players, and the like. Wireless power transfer systems typically include a primary side transmitter and a secondary side receiver. The primary transmitter is magnetically coupled to the secondary receiver by a magnetic coupling. The magnetic coupling may be achieved by a loosely coupled transformer having a primary winding formed in a primary transmitter and a secondary winding formed in a secondary receiver.

The primary side transmitter may include a power conversion unit, such as the primary side of a power converter. The power conversion unit is coupled to a power source and is capable of converting electrical power into a wireless power signal. The secondary side receiver is capable of receiving a wireless power signal through a loosely coupled transformer and converting the received wireless power signal into electric power suitable for a load.

As the power of wireless power transfer systems becomes higher and higher, efficient wireless power transfer between a transmitter and a receiver may need to be achieved. More particularly, achieving high efficiency wireless power transfer under various input and output conditions (e.g., different load currents and/or different rated input voltages of the receiver) has become a significant problem that presents challenges to the system design of wireless power transfer systems.

There is a need for a high performance power receiver that exhibits good behavior, such as high efficiency, under a variety of input and output conditions.

Disclosure of Invention

The above-mentioned problems and other problems are generally solved or circumvented, and technical advantages are generally achieved, by preferred embodiments of the present invention which provides a hybrid power converter in a receiver of a wireless power transmission system.

According to one embodiment, an apparatus comprises: a first switch, a capacitor and a second switch connected in series between an input voltage source and an output filter; a third switch connected between a common node of the first switch and the capacitor and a common node of the second switch and the output filter; and a fourth switch connected between a common node of the capacitor and the second switch and ground.

According to another embodiment, a method comprises: detecting a load current, an input voltage, and an output voltage of a power system including the hybrid converter; configuring the hybrid converter to operate in three different operating modes in response to different operating conditions; and in response to a change in an operating condition, configuring the hybrid converter to exit the first operating mode and enter the second operating mode.

According to yet another embodiment, a system comprises: a receiver coil configured to be magnetically coupled to the transmitter coil; a rectifier connected to the receiver coil; and a hybrid converter connected between the rectifier and the load, wherein the hybrid converter is configured to operate in three different operating modes in response to different load currents and output voltages of the system.

It is an advantage of embodiments of the present invention that a hybrid power converter in a receiver of a wireless power transfer system operates in a hybrid mode and a charge pump mode in order to achieve high efficiency. Furthermore, the combination of the hybrid mode, the charge pump mode, and the buck mode helps provide flexibility in different operating conditions.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

Drawings

For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

fig. 1 shows a block diagram of a wireless power transfer system according to various embodiments of the invention;

FIG. 2 shows a schematic diagram of a hybrid converter according to various embodiments of the invention;

FIG. 3 illustrates the principle of operation of the first stage of the hybrid mode according to various embodiments of the invention;

FIG. 4 illustrates the operating principle of the second stage of the hybrid mode according to various embodiments of the invention;

FIG. 5 illustrates the operational principle of the third stage of the hybrid mode according to various embodiments of the invention;

FIG. 6 illustrates the operating principle of the fourth stage of the hybrid mode according to various embodiments of the invention;

FIG. 7 illustrates the principle of operation of a first phase of a charge pump mode according to various embodiments of the invention;

FIG. 8 illustrates the principle of operation of a second stage of the charge pump mode according to various embodiments of the invention;

FIG. 9 illustrates the principle of operation of the first phase of the buck mode according to various embodiments of the invention;

FIG. 10 illustrates the principle of operation of the second stage of the buck mode according to various embodiments of the invention;

fig. 11 illustrates the principle of operation of a first stage of a hybrid converter operating in buck mode and automatic mode according to various embodiments of the invention;

FIG. 12 illustrates the principle of operation of a second stage of a hybrid converter operating in buck mode and automatic mode according to various embodiments of the invention;

FIG. 13 illustrates the principle of operation of an automatic mode according to various embodiments of the present invention;

FIG. 14 illustrates a mode transition principle according to various embodiments of the present invention;

FIG. 15 illustrates a flow diagram for applying a first control mechanism to the hybrid converter illustrated in FIG. 2 in accordance with various embodiments of the invention;

FIG. 16 illustrates a flow diagram for employing a second control mechanism for the hybrid converter illustrated in FIG. 2 in accordance with various embodiments of the invention;

FIG. 17 illustrates a flow diagram for applying a third control mechanism to the hybrid converter illustrated in FIG. 2 in accordance with various embodiments of the invention; and

fig. 18 illustrates a flow diagram for applying a fourth control mechanism to the hybrid converter illustrated in fig. 2, in accordance with various embodiments of the invention.

Corresponding numerals and symbols in the various drawings generally refer to corresponding parts unless otherwise indicated. The drawings are drawn for clarity in illustrating relevant aspects of various embodiments and are not necessarily drawn to scale.

Detailed Description

The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.

The present invention will be described with respect to preferred embodiments in a particular context, namely a hybrid power converter operating in different operating modes in order to increase the efficiency and performance of a wireless power transmission system. However, the present invention is also applicable to various power systems. Hereinafter, various embodiments will be explained in detail with reference to the drawings.

Fig. 1 shows a block diagram of a wireless power transfer system according to various embodiments of the invention. The wireless power transmission system 100 includes a power converter 104 and a wireless power transmission device 101 connected in cascade between an input power source 102 and a load 114. In some embodiments, the power converter 104 is employed in order to further improve the performance of the wireless power transfer system 100. In an alternative embodiment, the power converter 104 is an optional component. In other words, the wireless power transmission device 101 may be directly connected to the input power source 102.

The wireless power transmission apparatus 101 includes a power transmitter 110 and a power receiver 120. As shown in fig. 1, the power transmitter 110 includes a transmitter circuit 107 and a transmitter coil L1 connected in cascade. An input of the transmitter circuit 107 is coupled to an output of the power converter 104. The power receiver 120 includes a cascade-connected receiver coil L2, a resonant capacitor Cs, a rectifier 112, and a hybrid converter 113. As shown in fig. 1, the resonant capacitor Cs is connected in series with the receiver coil L2, and is further connected to the input of the rectifier 112. The output of the rectifier 112 is connected to the input of the hybrid converter 113. The output of the hybrid converter 113 is coupled to a load 114.

When the power receiver 120 is placed in proximity to the power transmitter 110, the power transmitter 110 is magnetically coupled to the power receiver 120 by a magnetic field. A loosely coupled transformer 115 is formed by a transmitter coil L1 as part of the power transmitter 110 and a receiver coil L2 as part of the power receiver 120. Thus, electrical power may be transferred from the power transmitter 110 to the power receiver 120.

In some embodiments, the power transmitter 110 may be within a charging pad. Transmitter coil L1 is placed below the upper surface of the charging pad. The power receiver 120 may be embedded within a mobile phone. When the mobile phone is placed near the charging pad, a magnetic coupling may be established between the transmitter coil L1 and the receiver coil L2. In other words, the transmitter coil L1 and the receiver coil L2 may form a loosely coupled transformer through which power is transferred between the power transmitter 110 and the power receiver 120. The strength of the coupling between the transmitter coil L1 and the receiver coil L2 can be quantified by a coupling coefficient k. In some embodiments, k is in the range from about 0.05 to about 0.9.

In some embodiments, after magnetic coupling is established between the transmitter coil L1 and the receiver coil L2, the power transmitter 110 and the power receiver 120 may form a power system through which power is wirelessly transferred from the input power source 102 to the load 114.

The input power source 102 may be a power adapter for converting a utility line voltage to a direct current (dc) voltage. Alternatively, the input power source 102 may be a renewable energy source such as a solar panel array. Further, the input power source 102 may be any suitable energy storage device, such as a rechargeable battery, a fuel cell, any combination thereof, and/or the like.

The load 114 represents the power consumed by a mobile device (e.g., a mobile phone) coupled to the power receiver 120. Alternatively, the load 114 may refer to one and/or more rechargeable batteries connected in series/parallel and coupled to the output of the power receiver 120. Further, the load 114 may be a downstream power converter such as a battery charger.

According to some embodiments, the transmitter circuit 107 may comprise the primary side switch of a full bridge converter. Alternatively, the transmitter circuit 107 may include the primary side switch of any other suitable power converter, such as a half-bridge converter, a push-pull converter, any combination thereof, and/or the like.

It should be noted that the power converters described above are only examples. Those skilled in the art will appreciate that other suitable power converters, such as those based on class E topologies (e.g., class E amplifiers), may alternatively be used depending on design needs and different applications.

The transmitter circuit 107 may also include a resonant capacitor (not shown). The resonant capacitor and the magnetic inductance of the transmitter coil may form a resonant tank. The resonant tank may also include a resonant inductor depending on design needs and different applications. In some embodiments, the resonant inductor may be implemented as an external inductor. In an alternative embodiment, the resonant inductor may be implemented as a connecting wire.

The power receiver 120 includes a receiver coil L2, the receiver coil L2 being magnetically coupled to the transmitter coil L1 after the power receiver 120 is placed in proximity to the power transmitter 110. Thus, power may be transferred to the receiver coil and further delivered to the load 114 through the rectifier 112. The power receiver 120 may include a secondary resonant capacitor Cs as shown in fig. 1.

The rectifier 112 converts the alternating polarity waveform received from the output of the receiver coil L2 into a single polarity waveform. In some embodiments, rectifier 112 includes a full wave diode bridge and an output capacitor. In an alternative embodiment, the full wave diode bridge may be replaced with a full wave bridge formed by switching elements such as n-type metal oxide semiconductor (NMOS) transistors.

Further, the rectifier 112 may be formed from other types of controllable devices, such as Metal Oxide Semiconductor Field Effect Transistor (MOSFET) devices, Bipolar Junction Transistor (BJT) devices, Super Junction Transistor (SJT) devices, Insulated Gate Bipolar Transistor (IGBT) devices, gallium nitride (GaN) based power devices, and/or the like. The detailed operation and structure of the rectifier 112 is well known in the art and therefore will not be discussed here.

The hybrid converter 113 is coupled between the rectifier 112 and the load 114. The hybrid converter 113 is a non-isolated power converter. The hybrid converter 113 may be configured as a buck converter, a charge pump converter, or a hybrid converter by controlling on/off of a switch of the hybrid converter 113.

The hybrid converter 113 may operate in different operating modes depending on design needs and different applications. More particularly, the hybrid converter 113 may operate in a buck mode when the load current is less than a predetermined current threshold and/or the input voltage is less than a predetermined voltage threshold. In the buck mode, the hybrid converter 113 is configured as a buck converter. The hybrid converter 113 may operate in a charge pump mode or a hybrid mode when the input voltage is greater than a predetermined voltage threshold and/or the load current is greater than a predetermined current threshold. More particularly, in some embodiments, the hybrid converter 113 may operate in a charge pump mode or a hybrid mode when the ratio of the output voltage of the hybrid converter to the input voltage of the hybrid converter is less than 0.5. In the charge pump mode, the hybrid converter 113 is configured as a charge pump converter. In the hybrid mode, the hybrid converter 113 is configured as a hybrid converter.

A schematic structure of the hybrid converter 113 will be described below with reference to fig. 2. Detailed configurations (e.g., different operating modes and their corresponding converter configurations) of the hybrid converter 113 are described below in conjunction with fig. 3-12.

In some embodiments, the input voltage of the hybrid converter 113 is in the range from about 18V to about 22V. The output voltage of the hybrid converter 113 is about 9V. One advantageous feature with the hybrid converter 113 is that a higher output voltage (e.g., 22V) can be achieved at the output of the rectifier 112. Such a high output voltage helps to reduce the current flowing through the receiver coil L2, thereby improving the efficiency of the power receiver 120.

Fig. 2 shows a schematic diagram of a hybrid converter according to various embodiments of the invention. The hybrid converter 113 includes a first switch Q1, a capacitor C_CPA second switch Q2, a third switch Q3, a fourth switch Q4, an output inductor Lo, and an output capacitor Co. As shown in fig. 2, the output inductor Lo and the output capacitor Co form an output filter. First switch Q1, capacitor C_CPAnd a second switch Q2 connected in series with the input voltage source V_INAnd an output filter. As shown in fig. 2, a first switch Q1 and a capacitor C are provided_CPThe common node of (a) is denoted CP +. Similarly, a second switch Q2 and a capacitor C_CPIs denoted CP-. The common node of the second switch Q2 and the output filter is denoted VX. As shown in fig. 2, a third switch Q3 is connected between CP + and VX. A fourth switch Q4 is connected between CP-and ground.

In some embodiments, capacitor C_CPActing as a charge pump capacitor. In the description of this general article, capacitor C_CPAlternatively referred to as charge pump capacitor C_CP。

According to an embodiment, the switches (e.g., switches Q1-Q4) may be Metal Oxide Semiconductor Field Effect Transistor (MOSFET) devices. Alternatively, the switching element may be any controllable switch, such as an Insulated Gate Bipolar Transistor (IGBT) device, an Integrated Gate Commutated Thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a Silicon Controlled Rectifier (SCR) device, a junction gate field effect transistor (JFET) device, a MOS Controlled Thyristor (MCT) device, or the like.

It should be noted that although fig. 2 illustrates switches Q1-Q4 as being implemented as single n-type transistors, those skilled in the art will appreciate that many variations, modifications, and alternatives are possible. For example, the switches Q1-Q4 may be implemented as p-type transistors depending on different applications and design needs. Further, each switch shown in fig. 2 may be implemented as a plurality of switches connected in parallel. Also, a capacitor may be connected in parallel with one switch to implement Zero Voltage Switching (ZVS)/Zero Current Switching (ZCS).

The hybrid converter 113 includes three different modes of operation, namely, a hybrid mode, a charge pump mode, and a buck mode. In some embodiments, the hybrid converter 113 operates in a buck mode when the output power of the wireless power system supports a 5W Baseband Power Profile (BPP) and a 5-15W Extended Power Profile (EPP). When the output power of the wireless power system supports 5-15W BPP and 15-20W EPP, the hybrid converter 113 operates in a hybrid mode or a charge pump mode. Further, the hybrid converter 113 may operate in a combination mode of a hybrid mode and a charge pump mode. In other words, the hybrid converter 113 may have a mode transition between the hybrid mode and the charge pump mode.

It should be noted that the power ranges used in the previous examples were chosen purely for demonstration purposes and are not intended to limit the various embodiments of the present invention to any particular power range.

In the hybrid mode, the hybrid converter 113 operates in four different phases. In each phase, depending on the input voltage V_INCapacitor C of charge pump_CPVoltage across and output voltage V_OUTThe current through the output inductor Lo may be ramped up or down in different combinations. In the hybrid mode, the voltage of the hybrid converter 113 may be adjusted to a predetermined voltage. Since the hybrid converter 113 in the hybrid mode has a strict voltage regulation, any load (e.g., a battery charger) may be connected to the output of the hybrid converter 113. The detailed operating principle of the hybrid mode will be described below in connection with fig. 3-6.

In the charge pump mode, the hybrid converter 113 operates in two different phases. In the charge pump mode, the voltage of the hybrid converter 113 is not adjusted. Since the hybrid converter 113 in the charge pump mode can vary in a wide range, only some loads (e.g., a battery charger with good transient performance) can be connected to the output of the hybrid converter 113. The detailed operating principle of the charge pump mode will be described below in connection with fig. 7-8.

In the buck mode, the hybrid converter 113 operates in two different phases. The second switch Q2 and the third switch Q3 are always open. Thus, the charge pump capacitor C_CPShort-circuited and is not part of the buck mode of operation. In each phase, depending on the input voltage V_INAnd an output voltage V_OUTThe current through the output inductor Lo may be ramped up or down in different combinations. The detailed operating principle of the buck mode will be described below in conjunction with fig. 9-10. Furthermore, the hybrid converter 113 may operate in an automatic mode in order to have a smooth transition between the buck mode and the charge pump mode. In the automatic mode, the charge pump capacitor is floating when the buck mode is applicable to the hybrid converter 113. The detailed operating principles of the buck mode and the automatic mode will be described below in conjunction with fig. 11-12.

To improve the performance of the wireless power transmission system 100 shown in fig. 1, the hybrid converter 113 may be configured to operate in a hybrid mode. The hybrid mode includes four different phases. Fig. 3-6 illustrate the operating principles of these four phases of the hybrid mode according to various embodiments of the invention.

Fig. 3 illustrates the principle of operation of the first stage of the hybrid mode according to various embodiments of the invention. During the first phase of the hybrid mode, switch Q3 is closed, as indicated by the arrow located above the symbol of switch Q3. Likewise, switch Q4 is closed, as indicated by the arrow above the symbol of switch Q4. Since switches Q1 and Q2 are open as shown in fig. 3, a conductive path is established as indicated by dashed line 302. The conductive path is formed by switch Q1, charge pump capacitor C_CPSwitch Q2 and output inductor Lo. The current flows from the input power source V through the conductive path shown in fig. 3_INTo the output voltage V_OUT。

During the first phase of the mixed mode, charge pump capacitor C is charged_CPCharging and, correspondingly, storing energy in a charge pump capacitor C_CPIn (1). The current through inductor Lo may ramp up or down depending on the voltage applied across inductor Lo. In some embodiments, when the input voltage V is_INLarger than the charge pump capacitor C_CPVoltage across and output voltage V_OUTWhen summed, the current through inductor Lo may ramp up and the energy stored in inductor Lo increases accordingly. The current slope S of the inductor Lo satisfies the following equation:

wherein V_CSIs a charge pump capacitor C_CPThe voltage across the terminals.

FIG. 4 illustrates the operating principle of the second stage of the hybrid mode according to various embodiments of the invention. During the second phase of the hybrid mode, switches Q1 and Q3 are closed, as indicated by the arrows located on their symbols. Since the switches Q2 and Q4 are open, a conductive path is established as indicated by the dashed line 402 shown in fig. 4. The conductive path is formed by switch Q4, switch Q2, and output inductor Lo. In some embodiments, switch Q4 provides a freewheeling path for the current flowing through the output inductor Lo.

During the second phase of the hybrid mode, the charge pump capacitor C_CPThe closed switches Q1 and Q3 are isolated. The current through inductor Lo ramps down and the energy stored in inductor Lo decreases accordingly. The current slope S of the inductor Lo satisfies the following equation:

fig. 5 illustrates the operating principle of the third stage of the hybrid mode according to various embodiments of the invention. During the third phase of the mixed mode, switches Q1 and Q2 are closedAs indicated by the arrows located on their symbols. Since the switches Q3 and Q4 are open, a conductive path is established as indicated by the dashed line 502 shown in fig. 5. The conductive path is formed by switch Q4, charge pump capacitor C_CPSwitch Q3 and output inductor Lo.

During the third phase of the hybrid mode, the current flows the charge pump capacitor C_CPDischarged and stored in the charge pump capacitor C_CPThe energy in (2) is reduced accordingly. In some embodiments, the current flowing through inductor Lo may ramp up and the energy stored in inductor Lo decreases accordingly. In the third phase of the hybrid mode, the current slope S of the inductor Lo satisfies the following equation:

FIG. 6 illustrates the operating principle of the fourth stage of the hybrid mode according to various embodiments of the invention. During the fourth phase of the hybrid mode, switches Q1 and Q3 are closed, as indicated by the arrows on their symbols. Since the switches Q2 and Q4 are open, a conductive path is established as indicated by the dashed line 602 shown in fig. 6. The conductive path is formed by switch Q4, switch Q2, and output inductor Lo. In some embodiments, switch Q4 provides a freewheeling path for the current flowing through the output inductor Lo.

During the fourth phase of the hybrid mode, the charge pump capacitor C_CPThe closed switches Q1 and Q3 are isolated. The current through inductor Lo ramps down and the energy stored in inductor Lo decreases accordingly. In the fourth phase of the hybrid mode, the current slope S of the inductor Lo satisfies the following equation:

it should be noted that during the hybrid mode, the hybrid converter 113 may operate in the four stages described above in connection with fig. 3-6. More particularly, the hybrid converter 113 may operate in four stages in sequential order as indicated by the stage numbers. In addition, the operation time of each stage may be determined by a controller (not shown). The controller senses various operating parameters (e.g., input voltage, output voltage, load current, any combination thereof, etc.). Based on the detected operating parameters, the controller sets the operating time for each stage.

Fig. 7 illustrates the principle of operation of the first phase of the charge pump mode according to various embodiments of the invention. During the first phase of the charge pump mode, the switch Q3 is closed, as indicated by the arrow located above the symbol of the switch Q3. Likewise, switch Q4 is closed, as indicated by the arrow above the symbol of switch Q4. Since the switches Q1 and Q2 are open, a conductive path is established as indicated by the dashed line 702 shown in fig. 7. The conductive path is formed by switch Q1, charge pump capacitor C_CPSwitch Q2 and output inductor Lo. The current flows from the input power source V through the conductive path shown in fig. 7_INTo the output voltage V_OUT. During the first phase of the charge pump mode, charge pump capacitor C is charged_CPCharging and, correspondingly, storing energy in a charge pump capacitor C_CPIn (1).

Fig. 8 illustrates the principle of operation of the second stage of the charge pump mode according to various embodiments of the invention. During the second phase of the charge pump mode, switches Q1 and Q2 are closed, as indicated by the arrows on their symbols. Since the switches Q3 and Q4 are open, a conductive path is established as indicated by the dashed line 802 shown in fig. 8. The conductive path is formed by switch Q4, charge pump capacitor C_CPSwitch Q3 and output inductor Lo. During the second phase of the charge pump mode, the current makes the charge pump capacitor C_CPDischarged and stored in the charge pump capacitor C_CPThe energy in (2) is reduced accordingly.

It should be noted that the output inductor Lo is an optional element during the charge pump mode. Depending on different applications and design needs, the output inductor Lo may be eliminated in order to further reduce the cost of the hybrid converter 113.

Fig. 9 illustrates the principle of operation of the first phase of the buck mode according to various embodiments of the invention. During the depressurization modeIn between, switches Q2 and Q3 are always open. In the first phase of the buck mode, the switch Q4 is closed, as indicated by the arrow above the symbol of the switch Q4. Since the switches Q1, Q2, and Q3 are open, the charge pump capacitor C is enabled by the open switches Q2 and Q3_CPShort-circuits and establishes a conductive path as indicated by the dashed line 902 shown in fig. 9. The conductive path is formed by switch Q1, switch Q3, and output inductor Lo. The current flows from the input power source V through the conductive path shown in fig. 9_INTo the output voltage V_OUT。

During the first phase of the buck mode, the current through the inductor Lo ramps up and the energy stored in the inductor Lo increases accordingly. The current slope S of the inductor Lo satisfies the following equation:

fig. 10 illustrates the principle of operation of the second stage of the buck mode according to various embodiments of the invention. During the second phase of the buck mode, switch Q1 is closed, as indicated by the arrow on its sign. A conductive path is established as indicated by the dashed line 1002 shown in fig. 10. The conductive path is formed by switch Q4, switch Q2, and output inductor Lo.

During the second phase of the buck mode, the current through inductor Lo ramps down and the energy stored in inductor Lo decreases accordingly. The current slope S of the inductor Lo satisfies the following equation:

fig. 11 illustrates the principle of operation of a first stage of a hybrid converter operating in buck mode and automatic mode according to various embodiments of the invention. The buck mode operating principle of the hybrid converter 113 is similar to that shown in fig. 9, except that during the first phase, the switch Q2 is closed. It should be noted that during the first phase shown in fig. 11, the charge pump capacitor C_CPAnd (5) floating. In addition, a charge pump capacitor C_CPHas been pre-charged to a voltage level approximately equal to twice the output voltage of the hybrid converter 113. Such a pre-charged voltage helps to achieve a smooth transition between buck mode and charge pump mode. In particular, the hybrid converter 113 may leave the buck mode and enter the charge pump mode smoothly, if desired.

Fig. 12 illustrates the principle of operation of the second stage of a hybrid converter operating in buck mode and automatic mode according to various embodiments of the invention. The buck mode operating principle of the hybrid converter 113 shown in fig. 12 is similar to the operating principle shown in fig. 10, except that during the second phase, the switch Q3 is closed. It should be noted that during the second phase, the charge pump capacitor C_CPAnd (5) floating. In addition, a charge pump capacitor C_CPHas been pre-charged to a voltage level approximately equal to twice the output voltage of the hybrid converter 113. Such a pre-charged voltage helps to achieve a smooth transition between buck mode and charge pump mode, since the charge pump capacitor C_CPWith a voltage ready for charge pump mode operation. Throughout this description, this smooth transition between buck mode and charge pump mode is referred to as auto mode.

FIG. 13 illustrates the principle of operation of an automatic mode according to various embodiments of the present invention. Depending on the different input and output voltages, the hybrid converter 113 is capable of operating in one of these three operating modes when the automatic mode is applied to the hybrid converter 113. As shown in FIG. 13, there may be two voltage thresholds, V_TH1And V_TH2. As shown in fig. 13, V_TH1Greater than V_TH2. In some embodiments, V_TH1Approximately equal to twice the output voltage of the hybrid converter 113 plus the hysteresis Voltage (VHYST). V_TH2Approximately equal to twice the output voltage of the hybrid converter 113 minus the hysteresis Voltage (VHYST). In some embodiments, the hysteresis Voltage (VHYST) is about 5% of the output voltage of the hybrid converter 113. It should be noted that 5% of the output voltage is only an example. Those skilled in the art will appreciate that the value of the hysteresis Voltage (VHYST) may be varied according to different applications and design needsAnd changed accordingly.

In operation, when the input voltage of the hybrid converter 113 is greater than V_TH1When so, the hybrid converter 113 is configured to operate in a hybrid mode. The operation principle of the hybrid mode is described in detail above in connection with fig. 3-6 and is therefore not described in further detail. Under some operating conditions, the input voltage of the hybrid converter 113 falls between V_TH1And V_TH2In the range in between, the hybrid converter 113 leaves the hybrid mode and enters the charge pump mode. The principle of operation of the charge pump mode is described in detail above in connection with fig. 7-8. Furthermore, the input voltage of the hybrid converter 113 may drop below V_TH2. As shown in fig. 13, the hybrid converter 113 leaves the charge pump mode and enters the buck mode. The operating principle of the buck mode is described in detail above in connection with fig. 10-11.

It should be noted that during the increase of the input voltage, the mode transition proceeds in a similar manner. For example, when the input voltage increases and exceeds V_TH2At this time, the hybrid converter 113 leaves the buck mode and enters the charge pump mode. Similarly, when the input voltage increases and exceeds V_TH1At this time, the hybrid converter 113 leaves the charge pump mode and enters the hybrid mode. A detailed mode transition process will be discussed in connection with fig. 14 below.

FIG. 14 illustrates a mode transition principle according to various embodiments of the present invention. As shown in fig. 14, mode transition between the hybrid mode and the charge pump mode is performed at a specific stage. When the hybrid converter 113 has a mode transition from the hybrid mode to the charge pump mode, the hybrid converter 113 exits at the end of the fourth phase of the hybrid mode and enters the first phase of the charge pump mode. On the other hand, when the hybrid converter 113 has a mode transition from the charge pump mode to the hybrid mode, the hybrid converter 113 exits at the end of the second phase of the charge pump mode and enters the first phase of the hybrid mode.

Fig. 14 further illustrates mode transitions between the charge pump mode and the buck mode. As shown in fig. 14, when the hybrid converter 113 has a mode transition from the charge pump mode to the buck mode, the hybrid converter 113 exits at the end of the second phase of the charge pump mode and enters the first phase of the buck mode. On the other hand, when the hybrid converter 113 has a mode transition from the buck mode to the charge pump mode, the hybrid converter 113 exits at the end of the second phase of the buck mode and enters the first phase of the charge pump mode.

Fig. 15 illustrates a flow diagram for applying a first control mechanism to the hybrid converter illustrated in fig. 2, in accordance with various embodiments of the invention. The flow diagram shown in fig. 15 is an example only, and should not unduly limit the scope of the claims. Those skilled in the art will appreciate numerous changes, alternatives, and modifications. For example, various steps shown in fig. 15 may be added, removed, replaced, rearranged, and repeated.

Referring back to fig. 2, the hybrid converter 113 includes four switches Q1, Q2, Q3, and Q4. Depending on different operating parameters, the hybrid converter 113 may operate in three different operating modes (i.e., a hybrid mode, a charge pump mode, and a buck mode). The hybrid mode includes four phases of operation; the charge pump mode comprises two phases of operation; and the buck mode includes two phases of operation. In operation, the hybrid converter 113 may exit one mode of operation and enter a different mode of operation depending on design needs and different applications. For example, the hybrid converter 113 may first operate in a charge pump mode and then enter a hybrid mode after a change in operating parameters occurs.

In some embodiments, the hybrid converter 113 may automatically switch from the charge pump mode to the hybrid mode when the output voltage of the hybrid converter 113 is greater than a predetermined voltage threshold or outside a predetermined output voltage range. For example, the hybrid converter 113 may exit the charge pump mode at the end of the first phase of the charge pump mode and enter into the hybrid mode at the beginning of the second phase of the hybrid mode. The operation mode transition between the charge pump mode and the hybrid mode is realized by the following steps.

At step 1502, the load and output voltage of the wireless power system are detected by a suitable sensing device or devices. The detected load and voltage are processed by the controller. In particular, the detected load current and/or output voltage is compared to a predetermined current and/or voltage threshold or range. In some embodiments, the controller may be a digital controller.

At step 1504, the hybrid converter 113 is configured to operate in a charge pump mode when the output voltage is within a predetermined output voltage range and the load current is greater than a predetermined current threshold. The operation of the charge pump mode is described in detail above in connection with fig. 7-8.

It should be noted that the predetermined output voltage range is merely an example, which should not unduly limit the scope of the claims. Those skilled in the art will appreciate numerous changes, alternatives, and modifications. For example, the input voltage tolerance of the load may be a factor in determining the operating mode of the hybrid converter 113.

At step 1506, the hybrid converter is configured to operate in a hybrid mode when the output voltage of the wireless power system is outside a predetermined range and the load current is greater than a predetermined current threshold. In some embodiments, during the operational mode transition, the hybrid converter 113 enters the second phase of the hybrid mode after completing the first phase of the charge pump mode.

Fig. 16 illustrates a flow diagram for applying a second control mechanism to the hybrid converter illustrated in fig. 2, in accordance with various embodiments of the invention. The flow diagram shown in fig. 16 is an example only, and should not unduly limit the scope of the claims. Those skilled in the art will appreciate numerous changes, alternatives, and modifications. For example, various steps shown in fig. 16 may be added, removed, replaced, rearranged, and repeated.

The operation mode transition control mechanism shown in fig. 16 is similar to the mechanism shown in fig. 15, except that the operation mode transition is made at a different time. It should be noted that the operational mode transition control mechanisms shown in fig. 15-16 may be employed individually or in combination to further improve the performance of the hybrid converter 113.

At step 1602, the load and output voltage of the wireless power system are detected by a suitable sensing device or devices. The sensed load and voltage are processed by the controller. In particular, the detected load current and/or output voltage is compared with a predetermined current and/or voltage threshold.

At step 1604, the hybrid converter 113 is configured to operate in a charge pump mode when the output voltage is within a predetermined range and the load current is greater than a predetermined current threshold. The operation of the charge pump mode is described in detail above in connection with fig. 7-8.

At step 1606, the hybrid converter 113 is configured to operate in a hybrid mode when the output voltage of the wireless power system is outside a predetermined range and the load is greater than a predetermined current threshold. In some embodiments, during the operational mode transition, the hybrid converter 113 enters the fourth phase of the hybrid mode after completing the second phase of the charge pump mode.

Fig. 17 illustrates a flow diagram for applying a third control mechanism to the hybrid converter illustrated in fig. 2, in accordance with various embodiments of the invention. The flowchart shown in fig. 17 is an example only, and should not unduly limit the scope of the claims. Those skilled in the art will appreciate numerous changes, alternatives, and modifications. For example, various steps shown in fig. 17 may be added, removed, replaced, rearranged, and repeated.

At step 1702, the load and output voltage of the wireless power system are detected by a suitable sensing apparatus or a plurality of sensing devices. The sensed load and voltage are processed by the controller. In particular, the detected load current and/or the detected output voltage is compared with a predetermined current and/or voltage threshold.

At step 1704, the hybrid converter 113 is configured to operate in a buck mode when the load current is less than the predetermined current threshold. The buck mode of operation is described in detail above in connection with fig. 9-10.

Fig. 18 illustrates a flow diagram for applying a fourth control mechanism to the hybrid converter illustrated in fig. 2, in accordance with various embodiments of the invention. The flow diagram shown in fig. 18 is an example only, and should not unduly limit the scope of the claims. Those skilled in the art will appreciate numerous changes, alternatives, and modifications. For example, various steps shown in fig. 18 may be added, removed, replaced, rearranged, and repeated.

At step 1802, the load and output voltage of the wireless power system are detected by a suitable sensing device or devices. The detected load and voltage are processed by the controller. In particular, the detected load current and/or output voltage is compared with a predetermined current and/or voltage threshold.

At step 1804, during a soft start of the hybrid converter 113, the hybrid converter 113 is configured to operate in a hybrid mode. The mixed mode operation is described in detail above in connection with fig. 3-6.

At step 1806, after the soft start process ends and the output voltage is fully established, the hybrid converter 113 is configured to operate in the charge pump mode. Mode transitions between the hybrid mode and the charge pump mode are described in detail above in connection with fig. 14-16 and are therefore not repeated in order to avoid unnecessary repetition.

It should be noted that the mode transition may be made during a soft start. For example, a mode transition from the hybrid mode to the charge pump mode may be made when the output voltage exceeds a predetermined value (e.g., 80% of the final output voltage).

Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.