Open circuit current sensing in a multiphase buck regulator
阅读说明:本技术 多相降压调节器中的开路电流感测 (Open circuit current sensing in a multiphase buck regulator ) 是由 郭晶虹 H·胡 T·吴 M·奥迪西尼 B·唐 H·佐杰尔 于 2019-08-01 设计创作,主要内容包括:本公开涉及多相降压调节器中的开路电流感测。例如,一种多相电压调节器,包括多个功率级、多个电流感测电路、控制器以及在控制器和一个或多个电流感测电路之间运行的电流感测接口。电流感测接口包括用于耦合至电流感测接口且被配置为支持单端或差分电流感测的每个电流感测电路的独立线路。调节器还包括多个上拉电路,每个上拉电路均连接至其中一条电流感测接口线路,并且具有比与其连接的线路更高的阻抗。控制器的故障检测电路基于连接至该线路的上拉电路确定电流感测接口线路中的对应一条是否具有开路故障,开路故障将线路上的电压上拉超过预定量。(The present disclosure relates to open circuit current sensing in a multi-phase buck regulator. For example, a multi-phase voltage regulator includes a plurality of power stages, a plurality of current sensing circuits, a controller, and a current sensing interface operating between the controller and one or more of the current sensing circuits. The current sensing interface includes independent lines for each current sensing circuit coupled to the current sensing interface and configured to support single ended or differential current sensing. The regulator also includes a plurality of pull-up circuits, each pull-up circuit connected to one of the current sensing interface lines and having a higher impedance than the line connected thereto. A fault detection circuit of the controller determines whether a corresponding one of the current sensing interface lines has an open fault that pulls up a voltage on the line by more than a predetermined amount based on a pull-up circuit connected to the line.)
1. A multi-phase voltage regulator comprising:
a plurality of power stages, each power stage configured to deliver a phase current to a load;
a plurality of current sensing circuits, each configured to provide a current sense signal representative of the phase current delivered to the load by a power stage coupled to the current sensing circuit;
a controller configured to control the plurality of power stages to regulate an output voltage provided to the load based at least in part on the current sense signal provided by the current sense circuit;
a current sensing interface operating between one or more of the current sensing circuits and the controller, the current sensing interface comprising a separate line for each current sensing circuit coupled with the current sensing interface and configured to support single-ended current sensing or differential current sensing; and
a plurality of pull-up circuits, each pull-up circuit connected to one of the current sensing interface lines and having a higher impedance than the line to which the pull-up circuit is connected,
wherein the controller includes a fault detection circuit configured to determine whether an individual one of the current sensing interface lines has an open fault based on the pull-up circuit connected to that line, wherein the open fault pulls up a voltage on that line by more than a predetermined amount.
2. The multi-phase voltage regulator of claim 1, wherein the current sensing interface comprises separate single current sense lines for each current sense circuit coupled with the current sensing interface and configured to support single-ended current sensing, and wherein a pull-up circuit is connected to a corresponding one of the single current sense lines.
3. The multi-phase voltage regulator of claim 1, wherein the current sensing interface comprises a separate current sense line and a separate current reference line for each current sensing circuit coupled with the current sensing interface and configured to support differential current sensing, and wherein a pull-up circuit is connected to a corresponding one of the current sense lines.
4. The multi-phase voltage regulator of claim 1, wherein the current sensing interface comprises a separate current sense line and a separate current reference line for each current sensing circuit coupled with the current sensing interface and configured to support differential current sensing, and wherein a pull-up circuit is connected to a corresponding one of the current reference lines.
5. The multi-phase voltage regulator of claim 1, wherein the current sensing interface includes a separate current sense line and a separate current reference line for each current sensing circuit coupled with the current sensing interface and configured to support differential current sensing, and wherein a first pull-up circuit is connected to a corresponding one of the current sense lines and a second pull-up circuit is connected to a corresponding one of the current reference lines.
6. The multiphase voltage regulator of claim 1, wherein at least one of said current sensing circuits is a DCR (direct current resistance) sensor comprising an RC network coupled in parallel with an inductor, and wherein said current sensing interface is configured to support differential current sensing and comprises a current sensing line coupled to a first terminal of a capacitor of said RC network and a current reference line coupled to a second terminal of said capacitor.
7. The multiphase voltage regulator of claim 6, wherein the pull-up circuit is connected to the current sense line.
8. The multiphase voltage regulator of claim 6, wherein the pull-up circuit is connected to the current reference line.
9. The multiphase voltage regulator of claim 6, wherein the first pull-up circuit is connected to the current sense line and a second pull-up circuit is connected to the current reference line.
10. The multi-phase voltage regulator of claim 1, wherein at least one of the current sensing circuits is a single ended output current mirror sensor integrated with a corresponding power stage, wherein the current sensing interface comprises a single current sense line configured to support single ended current sensing, and wherein a pull-up circuit is connected to the single current sense line.
11. The multi-phase voltage regulator of claim 1, wherein at least one of the current sensing circuits is a differential output current mirror sensor integrated with a corresponding power stage, and wherein the current sensing interface is configured to support differential current sensing and includes a current sense line connected to a first output node of the differential output current mirror sensor and a current reference line connected to a second output node of the differential output current mirror sensor.
12. The multiphase voltage regulator of claim 11, wherein a pull-up circuit is connected to the current sense line.
13. The multiphase voltage regulator of claim 11, wherein a pull-up circuit is connected to the current reference line.
14. The multiphase voltage regulator of claim 11, wherein a first pull-up circuit is connected to the current sense line and a second pull-up circuit is connected to the current reference line.
15. The multiphase voltage regulator of claim 1, wherein at least one of the pull-up circuits comprises a discrete pull-up resistor located proximate to the controller.
16. The multiphase voltage regulator of claim 1, wherein at least one of the pull-up circuits is integrated with the controller.
17. The multiphase voltage regulator of claim 16, wherein at least one pull-up circuit is a pull-up resistor, a transistor, or a current source.
18. The multiphase voltage regulator of claim 16, further comprising: a switch coupled to at least one pull-up circuit and configured to disconnect the at least one pull-up circuit from the current sensing interface when the multi-phase voltage regulator is regulating the output voltage provided to the load.
19. The multi-phase voltage regulator of claim 18, wherein when the at least one pull-up circuit is enabled by the switch and the multi-phase voltage regulator is regulating the output voltage provided to the load, the controller is configured to ignore voltage measurements taken on the current sensing interface.
20. The multi-phase voltage regulator of claim 1, wherein the fault detection circuit comprises a comparator circuit configured to compare a voltage measurement taken across the current sensing interface to a threshold detection voltage to determine whether a respective one of the current sensing interface lines has an open circuit fault.
21. The multi-phase voltage regulator of claim 1, wherein the controller comprises an ADC (analog-to-digital voltage regulator) configured to convert analog voltage measurements on the current sensing interface to corresponding digital values, and wherein the fault detection circuit is configured to determine whether an individual one of the current sensing interface lines has an open fault based on whether the digital values fall outside a predetermined range.
22. The multi-phase voltage regulator of claim 1, wherein the fault detection circuit is configured to determine whether an individual one of the current sense interface lines has an open fault during a startup mode of the multi-phase voltage regulator.
23. The multi-phase voltage regulator of claim 1, wherein the multi-phase voltage regulator is configured to begin regulating the output voltage provided to the load after exiting a startup mode and after responding to a voltage regulator enable signal received by the multi-phase voltage regulator, and wherein the fault detection circuit is configured to determine whether a respective one of the current sensing interface lines has an open circuit fault after the multi-phase voltage regulator exits the startup mode and before the multi-phase voltage regulator responds to the voltage regulator enable signal.
24. The multiphase voltage regulator of claim 1, wherein in response to the fault detection circuit detecting that an individual one of the current sense interface lines has an open circuit fault, the controller is configured to perform at least one of:
setting a fault in a status register;
simulating or zeroing phase currents of the power stage at which an open circuit fault is detected on the corresponding current sensing interface line;
disabling the power stage that detected an open circuit fault on the corresponding current sensing interface line while continuing to regulate the output voltage provided to the load by other power stages; and
and closing the controller.
25. A method of operating a multi-phase voltage regulator, the multi-phase voltage regulator having: a plurality of power stages, each power stage configured to deliver a phase current to a load; a plurality of current sensing circuits, each configured to provide a current sense signal representative of the phase current delivered to the load by a power stage coupled to the current sensing circuit; and a current sensing interface operating between one or more of the current sensing circuits and the controller, the current sensing interface comprising a separate line for each current sensing circuit coupled with the current sensing interface and configured to support single ended current sensing or differential current sensing, the method comprising:
connecting independent pull-up circuits to respective ones of the current sensing interface lines, each pull-up circuit having a higher impedance than the current sensing interface line to which it is connected; and
determining whether an individual one of the current sensing interface lines has an open fault based on the pull-up circuit connected to that line, wherein the open fault pulls up a voltage on that line by more than a predetermined amount.
26. The method of claim 25, further comprising:
disabling at least one of the pull-up circuits when the multi-phase voltage regulator is regulating an output voltage provided to the load.
27. The method of claim 25, further comprising:
ignoring voltage measurements taken on the current sensing interface when at least one of the pull-up circuits is enabled and the multi-phase voltage regulator is regulating the output voltage provided to the load.
28. The method of claim 25, wherein determining whether an individual one of the current sensing interface lines has an open fault comprises:
comparing a voltage measurement taken on the current sensing interface to a threshold detection voltage.
29. The method of claim 25, further comprising:
converting analog voltage measurements taken on the current sensing interface to corresponding digital values,
wherein based on whether the digital value falls outside a predetermined range, it is determined that an individual one of the current sense interface lines has an open fault.
30. The method of claim 25, wherein determining whether an individual one of the current sensing interface lines has an open fault comprises:
during a startup mode of the multi-phase voltage regulator, determining whether a respective one of the current sense interface lines has an open circuit fault.
31. The method of claim 25, further comprising:
after exiting the startup mode and after responding to a voltage regulator enable signal received by the multi-phase voltage regulator, beginning to regulate an output voltage provided to the load,
wherein determining whether a respective one of the current sense interface lines has an open fault comprises: determining whether a respective one of the current sense interface lines has an open fault after the multi-phase voltage regulator exits the startup mode and before the multi-phase voltage regulator responds to the voltage regulator enable signal.
32. The method of claim 25, further comprising:
in response to determining that an individual one of the current sense interface lines has an open fault, performing at least one of:
setting a fault in a status register;
simulating or zeroing phase currents of the power stage at which an open circuit fault is detected on the corresponding current sensing interface line;
disabling the power stage that detected an open circuit fault on the corresponding current sensing interface line while continuing to regulate the output voltage provided to the load by other power stages; and
and closing the controller.
Technical Field
The present disclosure relates generally to the field of detection circuits, and more particularly, to open circuit current sensing in a multi-phase buck regulator.
Background
There are many fault conditions in voltage regulators of the multiphase and parallel converter types that can still provide regulation under certain conditions but fail when operating conditions change. In some cases, if a fault condition is not detected and the operation of the voltage regulator significantly exceeds its operating limits, the fault may be catastrophic and may result in a severe heat release event, where component and system damage may alert, even causing a more serious event. In addition to output voltage sensing circuitry, voltage regulators utilize current sensing circuitry that enables a controller to monitor the current flowing through critical components in the regulator, such as a power switch or output sensor, for regulation, control, telemetry, and protection. In the case of an open current sense line, the controller may not be able to detect the open current sense line fault through a faulty manufacture or component failure, and the controller will continue to operate the voltage regulator as if there was no fault but with fault current sense information. By operating with fault current sensing information, the voltage regulator may operate significantly beyond the operating limits of the power component.
Therefore, a mechanism is needed to detect open current sense lines in voltage regulators of the multi-phase and parallel converter types.
Disclosure of Invention
According to one embodiment of a multiphase voltage regulator, the multiphase voltage regulator comprises: a plurality of power stages, each power stage configured to deliver a phase current to a load; a plurality of current sensing circuits, each current sensing circuit configured to provide a current sense signal representative of a phase current delivered to a load by a power stage coupled to the current sensing circuit; a controller configured to control the plurality of power stages to regulate an output voltage provided to a load based at least in part on a current sense signal provided by the current sense circuit; a current sensing interface operating between the controller and one or more current sensing circuits, the current sensing interface comprising a separate line for each current sensing circuit coupled with the current sensing interface and configured to support single ended current sensing or differential current sensing; and a plurality of pull-up circuits, each pull-up circuit connected to one of the current sensing interface lines and having a higher impedance than the line to which the pull-up circuit is connected. The controller includes a fault detection circuit configured to determine whether an individual one of the lines has an open fault based on a pull-up circuit connected to the line, wherein the open fault pulls up a voltage on the line by more than a predetermined amount.
The current sensing interface may include separate single current sense lines for each current sensing circuit coupled with the current sensing interface and configured to support single ended current sensing, and the pull-up circuit may be connected to a corresponding one of the single current sense lines.
The current sensing interface may include a separate current sense line and a separate current reference line for each current sensing circuit coupled with the current sensing interface and configured to support differential current sensing, and the pull-up circuit may be connected to a corresponding one of the current sense lines.
The current sensing interface may include a separate current sense line and a separate current reference line for each current sensing circuit coupled with the current sensing interface and configured to support differential current sensing, and the pull-up circuit may be connected to a corresponding one of the current reference lines.
The current sensing interface may include, separately or in combination, a separate current sense line and a separate current reference line for each current sensing circuit coupled with the current sensing interface and configured to support differential current sensing, and the first pull-up circuit may be connected to a corresponding one of the current sense lines and the second pull-up circuit may be connected to a corresponding one of the current reference lines.
Alone or in combination, the at least one current sensing circuit may be a DCR (direct current resistance) sensor comprising an RC network coupled in parallel with an inductor, wherein the voltage across the capacitor is proportional to the voltage drop across the parasitic DCR of the inductor and the inductor current. The current sensing interface may be configured to support differential current sensing and may include a current sense line coupled to a first terminal of a capacitor of the RC network and a current reference line coupled to a second terminal of the capacitor. The pull-up circuit may be connected to the current sense line and the pull-up circuit may be connected to the current reference line, or a first pull-up circuit may be connected to the current sense line and a second pull-up circuit may be connected to the current reference line.
The at least one current sensing circuit may be, alone or in combination, a single ended output current mirror sensor integrated with a corresponding power stage, the current sensing interface may include a single current sensing line configured to support single ended current sensing, and the pull-up circuit may be connected to the single current sensing line.
The at least one current sensing circuit may be, individually or in combination, a differential output current mirror sensor integrated with a corresponding power stage, and the current sensing interface may be configured to support differential current sensing and may include a current sense line connected to a first output node of the differential output current mirror sensor and a current reference line connected to a second output node of the differential output current mirror sensor. The pull-up circuit may be connected to the current sense line and the pull-up circuit may be connected to the current reference line, or a first pull-up circuit may be connected to the current sense line and a second pull-up circuit may be connected to the current reference line.
The at least one pull-up circuit may include, alone or in combination, a discrete pull-up resistor located proximate the controller.
The at least one pull-up circuit may be integrated with the controller, alone or in combination.
The at least one pull-up circuit may include, alone or in combination, a pull-up resistor, a transistor, or a current source integrated with the controller.
The switch may be coupled to the at least one pull-up circuit, alone or in combination, and configured to disconnect the at least one pull-up circuit from the current sensing interface line when the multi-phase voltage regulator is regulating the output voltage provided to the load.
The controller may be configured to ignore voltage measurements taken from the current sensing interface when, alone or in combination, one or more pull-up circuits are enabled by the switch and the multi-phase voltage regulator is regulating the output voltage provided to the load.
Alone or in combination, the fault detection circuit may include a comparator circuit configured to compare a voltage measurement taken across the current sensing interface with a threshold detection voltage to determine whether an individual one of the current sensing interface lines has an open fault.
The controller, alone or in combination, may include an ADC (analog-to-digital converter) configured to convert analog voltage measurements on the current sensing interface to corresponding digital values, and the fault detection circuit may be configured to determine whether an individual one of the current sensing interface lines has an open fault based on whether the digital values fall outside of a predetermined range.
Alone or in combination, the fault detection circuit may be configured to determine whether an individual one of the current sense interface lines has an open fault during a startup mode of the multi-phase voltage regulator.
Separately or in combination, the multi-phase voltage regulator may be configured to begin regulating the output voltage provided to the load after exiting the startup mode and after responding to a voltage regulator enable signal received by the multi-phase voltage regulator, and the fault detection circuit may be configured to determine whether a respective one of the current sensing interface lines has an open fault after the multi-phase voltage regulator exits the startup mode and before the multi-phase voltage regulator responds to the voltage regulator enable signal.
In response to the fault detection circuit detecting that the corresponding one of the current sense interface lines has an open fault, either alone or in combination, the controller may be configured to perform at least one of: setting a fault in a status register; simulating or zeroing phase currents of the power stage at which an open circuit fault is detected on the corresponding current sensing interface line; disabling the power stage that detected the open circuit fault on the corresponding current sensing interface line while continuing to regulate the output voltage provided to the load by the other power stages; and a shutdown controller.
According to one embodiment of a method of operating a multi-phase voltage regulator, the multi-phase voltage regulator has: a plurality of power stages, each power stage configured to deliver a phase current to a load; a plurality of current sensing circuits, each configured to provide a current sense signal representative of a phase current delivered to a load by a power stage coupled to the current sensing circuit; and a current sensing interface operating between the controller and one or more of the current sensing circuits, the current sensing interface comprising a separate line for each current sensing circuit coupled with the current sensing interface and configured to support single ended current sensing or differential current sensing, the method comprising: connecting independent pull-up circuits to respective ones of the current sensing interface lines, the pull-up circuits having a higher impedance than the current sensing interface lines to which they are connected; and determining whether a respective one of the lines has an open fault based on a pull-up circuit connected to the line, wherein the open fault pulls up a voltage on the line by more than a predetermined amount.
The method may further comprise: the at least one pull-up circuit is disabled when the multi-phase voltage regulator is regulating the output voltage provided to the load.
Alone or in combination, the method may further comprise: voltage measurements taken on the current sensing interface are ignored when the at least one pull-up circuit is enabled and the multi-phase voltage regulator is regulating the output voltage provided to the load.
Separately or in combination, determining whether a corresponding one of the current sensing interface lines has an open fault may include: the voltage measurement taken on the current sensing interface is compared to a threshold detection voltage.
Alone or in combination, the method may further comprise: the analog voltage measurements taken on the current sensing interface are converted to corresponding digital values, wherein based on whether the digital values fall outside a predetermined range, it can be determined that an individual one of the current sensing interface lines has an open circuit fault.
Separately or in combination, determining whether an individual one of the current sense interface lines has an open fault may include: during a startup mode of the multi-phase voltage regulator, it is determined whether a respective one of the current sense interface lines has an open fault.
Alone or in combination, the method may further comprise: after exiting the startup mode and after responding to the voltage regulator enable signal received by the multi-phase voltage regulator, beginning to regulate the output voltage provided to the load, and determining whether a respective one of the current sense interface lines has an open fault may include: after the multi-phase voltage regulator exits the startup mode and before the multi-phase voltage regulator responds to the voltage regulator enable signal, it is determined whether a respective one of the current sense interface lines has an open fault.
Alone or in combination, the method may further comprise: in response to determining that an individual one of the current sense interface lines has an open fault, performing at least one of: setting a fault in a status register; simulating or zeroing phase currents of the power stage at which an open circuit fault is detected on the corresponding current sensing interface line; disabling the power stage that detected the open circuit fault on the corresponding current sensing interface line while continuing to regulate the output voltage provided to the load by the other power stages; and a shutdown controller.
Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.
Drawings
The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. Features of the various illustrated embodiments may be combined unless they are mutually exclusive. Embodiments are shown in the drawings and described in detail in the following description.
Fig. 1 shows a block diagram of an embodiment of a multi-phase voltage regulator with open current sensing interface line fault detection.
FIG. 2 shows a block diagram of an embodiment of a pull-up circuit for detecting an open current sense interface line.
FIG. 3 shows a block diagram of an embodiment of a differential open current sensing interface line fault detection circuit.
Fig. 4 shows a block diagram of an embodiment of a single ended open current sensing interface line fault detection circuit.
FIG. 5 illustrates a block diagram of an embodiment of a DCR-based current sensing circuit used as part of an open current sensing interface line fault detection mechanism.
FIG. 6 illustrates a block diagram of an embodiment of an integrated differential current mirror based sensor used as part of an open current sensing interface line fault detection mechanism.
FIG. 7 illustrates a block diagram of an embodiment of an integrated single-ended current mirror based sensor using a portion of an over-open current sensing interface line fault detection mechanism.
Detailed Description
Embodiments described herein provide a mechanism for detecting an open circuit current sense line (in the case of single ended or differential current sensing) and/or an open circuit current reference line (in the case of differential current sensing) in a multi-phase voltage regulator. The open circuit current sense or reference line may be detected during power-up of the multi-phase voltage regulator, during regulation of the output voltage provided to the load, or after power-up and before the voltage regulator begins regulating the output voltage. The open circuit line detection mechanism described herein enables the controller to identify which phase of the voltage regulator has an open circuit current sense and/or reference line. The controller may respond to a detected open line fault, for example, by: setting a fault in a status register, simulating or zeroing phase currents of the power stage that detected the open fault, disabling the power stage that detected the open fault while continuing to regulate the output voltage provided to the load by other power stages, shutting down the controller, etc.
The term "line" as used herein describes a particular physical connection between the current sensing circuitry of the regulator power stage and the corresponding controller input pin. The circuitry described herein may include a single PCB (printed circuit board) trace, multiple traces across multiple PCBs, connectors carrying the same electrical signal, and the like. Such physical connections may also be described as signals, connections, wires, traces, interfaces, nodes, and the like. In each case, an open current sensing or reference "line" means that the associated connection between the current sensing circuitry and the corresponding controller input pin is not an electrical connection.
Fig. 1 illustrates one embodiment of a multi-phase Voltage Regulator (VR) 100. The
The
The controller 104 generates a control signal that is input to the
The controller 104 may further comprise a current sensing and balancing
The controller 104 may include a
The controller 104 may include a
The
A
In each case, if a corresponding one of the current
To mitigate open circuit faults on the
The controller 104 includes a
Controller 104 may perform open fault detection independently for all phases. In the absence of an open fault on the current
Fig. 2 illustrates one embodiment of pull-up
Fig. 2 also shows a scenario where the current
Fig. 3 illustrates one embodiment of a
Pull-
As explained previously herein, the corresponding current sense inputs IsenxX ', Irefx' of the controller 104 are amplified by an amplifier (amp)204 and converted to a digital signal Isenx _ dig by an ADC (analog to digital converter) 206 for processing by the current sense and
Instead of implementing the
Regardless of the type of fault detection implementation (comparator based, ADC based, etc.), for one or more pull-up
Fig. 4 illustrates another embodiment of the
Described below are embodiments of a
Fig. 5 shows an embodiment in which the at least one
For DCR-based current sensing circuits, the
Fig. 6 illustrates an embodiment in which at least one
For such a differential current mirror based current sensing circuit, the
Fig. 7 illustrates another embodiment of
The following describes embodiments when the VR controller 104 may implement the open circuit fault detection mechanisms described previously herein. The controller 104 may configure the
After exiting the startup mode, a VR enable signal is sent to the
After responding to the VR enable signal and after beginning to regulate the output voltage Vout provided to the
In response to the
Terms such as "first," "second," and the like, are used to describe various elements, regions, sections, etc. and are not intended to be limiting. Like terms refer to like elements throughout the description.
As used herein, the terms "having," "including," and the like are open-ended terms that indicate the presence of the stated elements or features, but do not exclude additional elements or features. The articles "a" and "an" and "the" are intended to include the plural and the singular, unless the context clearly dictates otherwise.
It is to be understood that features of the various embodiments described herein may be combined with each other, unless specifically noted otherwise.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.
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