Current limiting for voltage regulators
阅读说明:本技术 调压器的电流限制 (Current limiting for voltage regulators ) 是由 克里斯蒂安·文森特·索雷斯 于 2019-07-02 设计创作,主要内容包括:本说明书公开了用于限制调压器的输出电流的方法和装置,以在输出负载电流过载的情况下保护所述调压器免受部件过应力影响。在一些实施例中,作用于调压器的参考输入电压的限流电路可以限制所述调压器的最大输出负载电流。一旦所述限流电路检测到电流过载,就调整或减小所述参考电压以限制所述最大输出负载电流。另外,这些方法和装置可以与压摆率控制电路容易地耦合以同样限制涌入电流。(The present specification discloses methods and apparatus for limiting the output current of a voltage regulator to protect the voltage regulator from component overstress in the event of an output load current overload. In some embodiments, a current limiting circuit applied to a reference input voltage of a voltage regulator may limit a maximum output load current of the voltage regulator. Once the current limiting circuit detects a current overload, the reference voltage is adjusted or reduced to limit the maximum output load current. In addition, these methods and apparatus can be easily coupled with slew rate control circuitry to also limit inrush current.)
1. An apparatus, comprising:
a voltage regulator configured to output a regulated output voltage;
a reference voltage module configured to output a reference voltage to the voltage regulator;
a current sensor and comparator configured to sense an output current of the voltage regulator;
a current-limiting controller for controlling the current of the power supply,
wherein the controller is configured to limit the output current of the voltage regulator in response to the output of the current sensor and comparator by adjusting the reference voltage from the reference voltage module.
2. The apparatus of claim 1, wherein the first and second electrodes are disposed on opposite sides of the housing,
wherein the current sensor and comparator are further configured to compare the output current of the voltage regulator to a reference current to activate a current limit.
3. The apparatus of claim 1 or 2,
wherein the controller is further configured to limit the output current of the voltage regulator by adjusting the reference voltage from the reference voltage module in response to the output of the current sensor and comparator indicating overload.
4. The apparatus of any preceding claim, wherein the pressure regulator comprises:
an error amplifier is provided for the first and second transistors,
a voltage conversion stage for converting the voltage of the power supply,
a feedback circuit for the feedback of the feedback signal,
wherein the error amplifier is configured to receive inputs from both the reference voltage module and the feedback circuit and provide an output to the voltage conversion stage,
wherein the voltage conversion stage is configured to receive an input from the error amplifier and provide a voltage regulator output voltage to the feedback circuit,
wherein the current sensor and comparator are further configured to generate a copy of the voltage regulator output current.
5. The apparatus of claim 4, wherein the voltage conversion stage comprises:
an output power stage driven by an output power stage controller.
6. The apparatus of claim 5, wherein the output power stage controller is a linear controller or a switching controller.
7. The apparatus of claim 6, wherein the first and second electrodes are disposed on opposite sides of the substrate,
wherein the feedback circuit is a voltage control circuit or a current control circuit.
8. The apparatus of any preceding claim, wherein the reference voltage module further comprises a slew rate control,
wherein the slew rate control is coupled to the voltage regulator,
wherein the slew rate control limits the inrush current of the voltage regulator by controlling a slope of a change of an input to the voltage regulator.
9. The apparatus of claim 8, wherein the first and second electrodes are disposed on opposite sides of the substrate,
wherein the controller is further configured to limit the output current of the voltage regulator by adjusting an output voltage of the slew rate control.
10. A method for limiting an output current of a voltage regulator, the method comprising:
the reference voltage module inputs a reference voltage to the voltage regulator;
the voltage regulator outputs a regulated output voltage and an output current, wherein the output voltage is based on the input reference voltage;
a current sensor and comparator sense the output current of the voltage regulator;
a controller limits the output current of the voltage regulator,
wherein the controller limits the output current of the voltage regulator in response to the output of the current sensor and comparator by adjusting the reference voltage from the reference voltage module.
Technical Field
The described embodiments relate generally to methods and apparatus for providing current limiting and, more particularly, to methods and apparatus for providing current limiting for voltage regulation.
Background
The current limiting circuit may be used to protect the voltage regulator from component overstress in the event of an output load current overload. However, typical current limiting circuits may have instability and other problems.
Accordingly, there is a strong incentive to improve current limiting circuits and mitigate instability and other problems.
Disclosure of Invention
In general, the current limiting circuit may sense the output current on the primary amplification stage and the counter reaction to alter the characteristics of the amplifier of the voltage regulator. However, this approach may have the disadvantage of modifying the loop response and may cause instability problems. The present specification discloses methods and systems for limiting the output current of a voltage regulator that may address potential stability issues and provide other benefits in regulator power-on or current-limiting use cases.
In some embodiments, this specification describes a current limiting circuit that can limit the maximum output load current by acting on a reference input voltage of a regulator. Once the current limiting circuit detects a current overload, the reference voltage is adjusted (or, for example, reduced) to limit the output load current.
These embodiments may be used to manage current limiting during output load current overloads to protect the regulator and to overstress regulator components. These embodiments limit the current when the output load current is overloaded by presenting a current limiting loop outside of the regulator feedback loop. Furthermore, this current limiting loop can take over from the regulator feedback loop when the output load current is overloaded. This may address potential stability issues in regulator power-on or current limited use situations. This also simplifies the overall regulator stability analysis when the current limit loop is outside the regulator feedback loop.
The present invention provides an apparatus comprising: (a) a voltage regulator configured to output a regulated output voltage; (b) a reference voltage module configured to output a reference voltage to the voltage regulator; (c) a current sensor and comparator configured to sense an output current of the voltage regulator; (d) a current limit controller, (e) wherein the controller is configured to limit the output current of the voltage regulator by adjusting an output of the current sensor and comparator from the reference voltage response domain of the reference voltage module.
In some embodiments, the current sensor and comparator are additionally configured to compare the output current of the voltage regulator to a reference current to activate current limiting.
In some embodiments, the controller is additionally configured to limit the output current of the voltage regulator by adjusting the reference voltage from the reference voltage module in response to the output of the current sensor and comparator indicating overload.
In some embodiments, the voltage regulator comprises: (a) an error amplifier, (b) a voltage conversion stage, (c) a feedback circuit, (d) wherein the error amplifier is configured to receive inputs from both the reference voltage module and the feedback circuit and provide an output to the voltage conversion stage, (e) wherein the voltage conversion stage is configured to receive an input from the error amplifier and provide a regulator output voltage to the feedback circuit, (f) wherein the current sensor and comparator are additionally configured to generate a copy of the regulator output current.
In some embodiments, the voltage conversion stage comprises: an output power stage driven by an output power stage controller.
In some embodiments, the output power stage controller is a linear controller or a switching controller.
In some embodiments, the feedback circuit is a voltage control circuit or a current control circuit.
In some embodiments, the reference voltage module additionally includes a slew rate control, wherein the slew rate control is coupled to the voltage regulator, wherein the slew rate control limits an inrush current of the voltage regulator by controlling a slope of a change of an input to the voltage regulator.
In some embodiments, the controller is further configured to limit the output current of the voltage regulator by adjusting an output voltage of the slew rate control.
In some embodiments, the reference voltage module is capable of simultaneously providing a normal operating reference voltage that is not regulated by the controller to another voltage regulator for current limiting.
The present invention also provides a method for limiting the output current of a voltage regulator, the method comprising: (a) the reference voltage module inputs a reference voltage to the voltage regulator; (b) the voltage regulator outputs a regulated output voltage and an output current, wherein the output voltage is based on an input reference voltage; (c) a current sensor and comparator sense the output current of the voltage regulator; (d) a controller limits the output current of the voltage regulator, (e) wherein the controller adjusts the output current of the voltage regulator in response to the output of the current sensor and comparator by adjusting the reference voltage from the reference voltage module.
In some embodiments, the method additionally comprises: the current sensor and comparator compares the output current of the voltage regulator to a reference current to activate an output current limit of the controller.
In some embodiments, the step of the voltage regulator outputting the output voltage and the output current comprises: (a) an error amplifier receives inputs from both the reference voltage module and a feedback circuit, (b) the error amplifier provides an output to a voltage conversion stage, (c) the voltage conversion stage provides a regulator output voltage to the feedback circuit, (d) the voltage conversion stage provides a regulator output current to the current sensor and comparator.
In some embodiments, the reference voltage module additionally includes a slew rate control, wherein the slew rate control is coupled to the voltage regulator, wherein the slew rate control limits an inrush current of the voltage regulator by controlling a slope of a change of an input to the voltage regulator.
In some embodiments, the controller additionally limits the output current of the voltage regulator by adjusting an output voltage of the slew rate control.
The invention provides a computer program product comprising executable instructions encoded in a non-transitory computer readable medium, which when executed by a system, perform or control a method for limiting an output current of a voltage regulator, the method comprising: (a) the reference voltage module inputs a reference voltage to the voltage regulator; (b) the voltage regulator outputs a regulated output voltage and an output current, wherein the output voltage is based on an input reference voltage; (c) a current sensor and comparator sense the output current of the voltage regulator; (d) a controller limits the output current of the voltage regulator, (e) wherein the controller adjusts the output current of the voltage regulator in response to the output of the current sensor and comparator by adjusting the reference voltage from the reference voltage module.
The above summary is not intended to represent each exemplary embodiment within the scope of the present or future set of claims. Additional example embodiments are discussed in the figures and detailed description below. Other aspects and advantages of embodiments of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.
Drawings
Fig. 1 illustrates a functional block diagram of a first apparatus for limiting an output current of a voltage regulator according to some embodiments of the present invention.
Fig. 2A illustrates a circuit diagram of the apparatus of fig. 1 according to some embodiments of the invention.
Fig. 2B illustrates a circuit diagram of a reference voltage module (which is part of the apparatus of fig. 2A) according to some embodiments of the invention.
Fig. 2C illustrates a circuit diagram of a voltage regulator (which is part of the device of fig. 2A) according to some embodiments of the present invention.
Fig. 2D illustrates a circuit diagram of a current limit controller and current sensors and comparators (which are part of the apparatus of fig. 2A) according to some embodiments of the invention.
Fig. 3 illustrates a functional block diagram of a second apparatus for limiting the output current of a voltage regulator (the second apparatus additionally including a slew rate control), according to some embodiments of the present invention.
Fig. 4A illustrates a circuit diagram of the apparatus of fig. 3 according to some embodiments of the invention.
Fig. 4B illustrates a circuit diagram of a reference voltage module (which includes a slew rate control and is part of the apparatus of fig. 4A) according to some embodiments of the present invention.
Fig. 4C illustrates a circuit diagram of a voltage regulator (which is part of the fig. 4A device) according to some embodiments of the present invention.
Fig. 4D illustrates a circuit diagram of a current limit controller and current sensors and comparators (which are part of the apparatus of fig. 4A) according to some embodiments of the invention.
Fig. 5 illustrates a method for limiting the output current of a voltage regulator according to some embodiments of the invention.
Detailed Description
It will be readily understood that the components of the embodiments, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the various embodiments, as represented in the figures, is not intended to limit the scope of the disclosure, but is merely representative of the various embodiments. While various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by this detailed description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.
Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, in view of the description herein, that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.
The present specification discloses methods and systems for limiting the output current of a voltage regulator. In some embodiments, this specification describes a current limiting circuit for a voltage regulator. The current limiting circuit is used to protect the regulator from component overstress in the event of an output load current overload. In some embodiments, the current limiting circuit may limit the maximum output load current by acting on a reference input voltage of the regulator. Once the current limiting circuit detects a current overload, the reference voltage is reduced to limit the output load current. Thus, in some embodiments, a current limiting circuit acting on a reference voltage input of the voltage regulator may limit the maximum output load current of the voltage regulator.
In some embodiments, this specification describes methods and apparatus for managing current limits and limiting maximum output load current. This helps protect the regulator by acting on the reference input voltage rather than directly on the regulator output power stage. The current limiting circuit reduces the reference input voltage of the regulator in the event of an overload of the output load current. This prevents overstressing of the regulator components, since the current limitation is achieved by reference to the input voltage. This also does not affect the reference voltage module performance. For example, no additional serial components are present on the reference voltage path and no current is loaded on the reference voltage during normal operation. In addition, these methods and apparatus can be easily coupled with slew rate control circuitry to also limit inrush current.
In some embodiments, the present specification describes methods and apparatus that allow for the simplest stability analysis, because:
a. the current limiting circuit takes over from the regulator feedback loop by reference to the input voltage;
b. the current limiting loop is outside the regulator feedback loop;
c. the current limiting loop does not require much gain to limit the maximum output load current of the regulator;
d. the current limit loop and the regulator feedback loop do not conflict in terms of stability.
Typically, current limit stability problems occur during the power-up of the regulator due to interference with the regulator primary loop. This problem is now overcome by placing the current limit loop outside the regulator feedback loop.
In some embodiments, the present specification describes methods and apparatus to avoid overstressing regulator components during current limiting, since overstressing smoothly biases the entire regulator according to the reference input voltage value.
Fig. 1 illustrates a functional block diagram of a
In fig. 1, a
The
In some embodiments, the
Fig. 2A illustrates a circuit diagram of the apparatus of fig. 1 according to some embodiments of the invention. In particular, fig. 2A illustrates an example embodiment of a circuit implementation of the
In fig. 2A, a
For example, the
The
Again, similarly, the
Fig. 2A shows an overview of the
As shown in fig. 2A and 2C, the
Fig. 3 illustrates a functional block diagram of a second apparatus 300 for limiting the output current of a voltage regulator (the second apparatus 300 additionally including a slew rate control 380), according to some embodiments of the present invention. In fig. 3, a second means 300 for limiting the output current of the voltage regulator includes a reference voltage module 310, a voltage regulator 320, a current sensor and comparator 360, and a current limit controller 370. Fig. 3 also shows that the voltage regulator 320 includes an error amplifier 330, a voltage conversion stage 340, and a feedback circuit 350. Fig. 3 shows that slew rate control 380 is included in reference voltage module 310. However, in some embodiments, the slew rate control may be separate from the reference voltage module (note: not shown in FIG. 3). In some embodiments, slew rate control 380 may be arranged to be located between reference voltage module 310 and voltage regulator 320 (note: not shown in fig. 3). In some embodiments, reference voltage module 310 may be arranged to be located between slew rate control 380 and voltage regulator 320 (note: not shown in fig. 3). In some embodiments, slew rate control 380 and reference voltage module 310 may have a combined output to voltage regulator 320. In some embodiments, the slew rate control and the reference voltage module may have separate outputs to the voltage regulator.
Fig. 3 is very similar to fig. 1, except that second device 300 additionally includes a slew rate control 380 for limiting the output current of the voltage regulator. A slew rate control is added to limit the inrush current of the regulator by controlling the slope of the change in input to the regulator at startup. Slew rate is defined as the voltage or current change per unit time. Thus, the slew rate control 380 may limit the inrush current of the voltage regulator 320 by controlling the slope of the change of the input (e.g., voltage) to the voltage regulator. For example, in some embodiments, the slew rate control may limit the inrush current of the voltage regulator by reducing the slope of the change in the input voltage to the voltage regulator.
In some embodiments, the reference voltage module 310 additionally includes a slew rate control 380, wherein the slew rate control 380 is coupled to the voltage regulator 320, wherein the slew rate control 380 limits the inrush current of the voltage regulator 320 by controlling the slope of the change of the input to the voltage regulator 320.
In some embodiments, the controller 370 is additionally configured to limit the output current (Iout324) of the voltage regulator 320 by adjusting the output voltage of the slew rate control. In some embodiments, the controller 370 may adjust the output voltage of the slew rate control such that the voltage regulator 320 receives an "adjusted" reference voltage and the output current (Iout324) of the voltage regulator 320 is adjusted accordingly.
In some embodiments, reference voltage module 310 can simultaneously provide a normal operating reference voltage to another voltage regulator that is not regulated by current limit controller 370. This may mean that, in some embodiments, the reference voltage module 310 is coupled to the voltage regulator 320 and another voltage regulator. Current limit controller 370 may then adjust the output voltage of the slew rate control such that voltage regulator 320 receives an "adjusted" reference voltage, while another voltage regulator receives an "unadjusted" reference voltage (which may be considered a normal operating reference voltage that is not adjusted by current limit controller 370).
Fig. 4A illustrates a circuit diagram of the apparatus of fig. 3 according to some embodiments of the invention. Specifically, fig. 4A illustrates an example embodiment of a circuit implementation of the apparatus 300 of fig. 3. Accordingly, in view of the description of FIG. 4A, one skilled in the relevant art will recognize that the present invention may be practiced with other embodiments of the circuit implementation of apparatus 300 of FIG. 3, and that such other embodiments are not shown in this specification.
In fig. 4A, a circuit 400 for limiting the output current of a voltage regulator includes a
The circuit 400 pertaining to the exemplary embodiment of the apparatus 300 operates in a manner similar to the apparatus 300. Thus, for example, fig. 4A shows
Again, similarly, the
Fig. 4A shows an overview of the circuit 400, while fig. 4B, 4C, and 4D give close-up views of various portions of the circuit 400. Specifically, FIG. 4B illustrates a close-up view of the
As shown in fig. 4A, 4B, 4C, and 4D: the voltage regulator 420 and
Fig. 5 illustrates a
In this specification, example embodiments have been presented with a selected set of details. However, it should be understood by those of ordinary skill in the art that many other example embodiments may be practiced that include a different selected set of these details. The following claims are intended to cover all possible example embodiments.
Although the operations of one or more methods herein are shown and described in a particular order, the order of the operations of each method may be altered so that certain operations may be performed in an inverse order or so that certain operations may be performed, at least in part, concurrently with other operations. In another embodiment, instructions or sub-operations of different operations may be performed in an intermittent and/or alternating manner.
It should also be noted that at least some of the operations of the methods may be implemented using software instructions stored on a computer-usable storage medium for execution by a computer. For example, embodiments of a computer program product include a computer usable storage medium for storing a computer readable program, which when executed on a computer, causes the computer to perform operations, as described herein.
The computer-usable or computer-readable medium may be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a Random Access Memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Examples of optical disks include read-only memory compact disks (CD-ROMs), read/write compact disks (CD-Rs/Ws), Digital Video Disks (DVDs), and Blu-ray disks.
The various aspects, embodiments, implementations or features of the described embodiments may be used alone or in any combination. Various aspects of the described embodiments may be implemented in software, hardware, or a combination of hardware and software.
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. The description is not intended to be exhaustive or to limit the described embodiments to the precise form disclosed. It will be apparent to those skilled in the art that many modifications and variations are possible in light of the above teaching.