Overshoot protection circuit, voltage regulator, chip and electronic device

Abstract

An overshoot protection circuit (100), a voltage regulator, a chip and an electronic device. The overshoot protection circuit (100) is applied to a power source module, and the overshoot protection circuit (100) comprises an overshoot protection module (110) and a selection module (120), wherein the overshoot protection module (110) is used for receiving an output voltage of the power source module, generating an overshoot voltage or an undershoot voltage when a load changes, and outputting a control signal when the overshoot protection circuit (100) starts to operate and a voltage is located outside a preset load voltage range; and by means of an overshoot voltage or undershoot voltage generated by the power source module during a load transient, the selection module (120) turns on a corresponding switch tube to charge or discharge an LDO gate capacitor, thereby optimizing the transient performance of an LDO. By limiting within a given voltage range an overshoot voltage and an undershoot voltage that are output and generated by a power source module during load switching, the magnitude of a peak voltage is controlled at any instant of load switching in the power source module, thereby avoiding the generation of a relatively large peak voltage.

Description

Overshoot protection circuits, voltage regulators, chips and electronic devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on September 27, 2023, with application number 202311262150.5 and invention name “Overshoot protection circuit, voltage regulator, chip and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present invention relates to the field of circuit technology, and in particular to an overshoot protection circuit, a voltage stabilizer, a chip and an electronic device. Background Art

[0004] Low-dropout linear regulators (LDOs) are widely used in chip design due to their high precision, high efficiency, low power consumption, and stable output. However, during the instant of LDO load switching, the power transistor cannot respond to the load change in a timely manner, resulting in a disparity between the current generated by the power transistor and the load current, causing large voltage spikes (this spike voltage includes both overshoot and undershoot). The overshoot caused by load current switching can be reduced by adding load capacitance, but large load capacitance consumes chip area. Furthermore, using load capacitance to mitigate overshoot voltage cannot effectively control the maximum output voltage deviation range. If the LDO experiences excessive overshoot voltage during load switching, it may cause the chip to reset or even damage the chip.

[0005] Summary of the Invention

[0006] The present invention provides an overshoot protection circuit, a voltage stabilizer, a chip and an electronic device, the main purpose of which is to protect a power module, prevent a spike voltage generated at the moment of load current switching, and avoid damage to the power module.

[0007] In a first aspect, an embodiment of the present invention provides an overshoot protection circuit, which is applied to a power module. The overshoot protection circuit includes an overshoot protection module and a selection module, wherein:

[0008] The overshoot protection module is used to detect the output voltage of the power module and output a control signal when the output voltage is outside a preset voltage range;

[0009] The selection module is used to charge or discharge the parasitic capacitance of the first power tube in the power module according to the control signal when the output voltage is outside the preset voltage range, so that the power module output optimizes the peak voltage caused by load switching.

[0010] Furthermore, the preset voltage range includes a preset maximum voltage threshold and a preset minimum voltage threshold, and the control signal includes a first control signal and a second control signal, wherein:

[0011] The overshoot protection module is configured to output the first control signal when the output voltage is greater than the preset maximum voltage threshold, and output the second control signal when the output voltage is less than the preset minimum voltage threshold;

[0012] The selection module is configured to control the charging of the parasitic capacitor according to the first control signal, and to control the discharging of the parasitic capacitor according to the second control signal.

[0013] Furthermore, the overshoot protection module includes an overvoltage detection unit and an undervoltage detection unit, wherein:

[0014] The overvoltage detection unit includes a second power tube, and the overvoltage detection unit is used to output a first comparison signal when the output voltage is greater than a preset maximum voltage threshold, and control the second power tube to output a first control signal according to the first comparison signal;

[0015] The undervoltage detection unit includes a third power tube, and the undervoltage detection unit is used to output a second comparison signal when the output voltage is less than a preset minimum voltage threshold, and control the third power tube to output a second control signal according to the second comparison signal.

[0016] Furthermore, the overvoltage detection unit includes a first comparator, the input end of the first comparator is used to connect to the output end of the power supply module, the output end of the first comparator is connected to the second power tube, the second power tube is used to connect to an external power supply, and the second power tube outputs the first control signal.

[0017] Furthermore, the undervoltage detection unit includes a second comparator, the input end of the second comparator is used to connect to the output end of the power supply module, the output end of the second comparator is connected to the third power tube, the third power tube is used to be grounded, and the third power tube outputs the second control signal.

[0018] Furthermore, the undervoltage detection unit includes a second comparator, the input end of the second comparator is used to connect to the output end of the power supply module, the output end of the second comparator is connected to the third power tube, the third power tube is used to be grounded, and the third power tube outputs the second control signal.

[0019] Furthermore, the control module is used to perform an XOR operation on the first comparison signal and the second comparison signal, and output the selection signal.

[0020] In a second aspect, an embodiment of the present invention provides a voltage stabilizer, comprising an overshoot protection circuit as provided in the first aspect.

[0021] In a third aspect, an embodiment of the present invention provides a chip, comprising an overshoot protection circuit as provided in the first aspect, or a voltage regulator as provided in the second aspect.

[0022] In a fourth aspect, an embodiment of the present invention provides an electronic device, comprising an overshoot protection circuit as provided in the first aspect, or a voltage regulator as provided in the second aspect, or a chip as provided in the third aspect.

[0023] The present invention proposes an overshoot protection circuit, voltage stabilizer, chip, and electronic device. When the output voltage of a power module is outside a preset voltage range, the overshoot protection module controls the charging or discharging of the parasitic capacitance of a first power transistor in the power module based on a control signal corresponding to the output voltage, thereby mitigating overvoltage or undervoltage conditions in the output voltage. At the moment when a transient load current occurs at the output end of the power module, the first power transistor can also respond promptly, thereby improving transient characteristics. In embodiments of the present invention, the output voltage of the power module is within a preset voltage range. The present invention successfully limits the overshoot and undershoot voltages generated by the power module output at the moment of load switching to within a given voltage range. The magnitude of the overshoot and undershoot voltages can be controlled at any extremely brief moment during load switching of the power module, thereby avoiding overshoot. This does not require a significant increase in chip area. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a circuit diagram of a voltage stabilizer provided by the prior art;

[0025] FIG2 is a schematic diagram of the prior art when the load current switches from a light load to a heavy load;

[0026] FIG3 is a schematic diagram of the prior art when the load current switches from heavy load to light load;

[0027] FIG4 is a schematic structural diagram of an overshoot protection circuit provided by an embodiment of the present invention;

[0028] FIG5 is a circuit diagram of an overshoot protection module according to an embodiment of the present invention;

[0029] FIG6 is a schematic structural diagram of an overshoot protection circuit provided by an embodiment of the present invention;

[0030] FIG7 is a circuit diagram of a control module provided in an embodiment of the present invention;

[0031] FIG8 is a circuit diagram of an overshoot protection circuit applied to a voltage regulator according to an embodiment of the present invention;

[0032] FIG9 is a comparison diagram of simulation results when the load switches from light load to heavy load when the LDO is equipped with an overshoot protection circuit and when the LDO is not equipped with an overshoot protection circuit in an embodiment of the present invention;

[0033] FIG10 is a comparison diagram of simulation results when the load switches from heavy load to light load with and without an overshoot protection circuit added to the LDO according to an embodiment of the present invention.

[0034] Reference numerals:

[0035] 110, overshoot protection module; 120, selection module;

[0036] 111, overvoltage detection unit; 112, undervoltage detection unit;

[0037] 113, a first comparator; 114, a second comparator;

[0038] 130, control module; Q1, first power tube;

[0039] Q2, the second power tube; Q3, the third power tube;

[0040] 100, overshoot protection circuit.

[0041] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0042] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0043] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0044] In the embodiments of the present application, at least one refers to one or more; a plurality refers to two or more. In the description of the present application, words such as "first", "second", and "third" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0045] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, the terms "including," "comprising," "having," and their variations in this specification all mean "including but not limited to," unless otherwise specifically stated.

[0046] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0047] A voltage regulator provided by the prior art is shown in FIG1 , in which VDD represents the power supply, EA represents the error amplifier, MPOW represents the power tube, VREF represents the reference voltage, RFB1 and RFB2 both represent resistors, RL represents the load resistor, CL represents the load capacitor, V OUT Represents the output voltage; the voltage regulator includes an error amplifier, a power tube, a feedback network composed of resistors RFB1 and RFB2, and an output load. For the voltage regulator in a balanced state, the current generated by the power tube is equal to the load current, and the output voltage of the voltage regulator V OUT Stablize.

[0048] However, at the moment of load switching in the voltage regulator, due to the parasitic capacitance inside the power tube, the power tube cannot respond to the load change in time, resulting in the current generated by the power tube being unequal to the load current. In the prior art, when the load current switches from light load to heavy load, as shown in Figure 2, according to Kirchhoff's current law, the current I generated by the power tube DS,MPOW Less than the load current I LOAD , the load capacitor CL reaches equilibrium by discharging. At this time, the charge accumulated in the capacitor CL is released instantly, and the discharge current is ΔI OUT =|I DS,POW -ILOAD |, resulting in an output voltage V OUT is pulled low, creating an undervoltage condition.

[0049] In the prior art, when the load current switches from heavy load to light load, as shown in FIG3 , according to Kirchhoff’s current law, the current I generated by the power tube DS,MPOW Greater than the load current I LOAD , the load capacitor CL begins to charge, at this time the charge of the capacitor CL begins to accumulate, and the discharge current is ΔI OUT＝ |I DS,POW -I LOAD |, output voltage V OUT It is lifted up instantly, causing an overvoltage condition.

[0050] In view of the above situation, an embodiment of the present invention provides an overshoot protection circuit 100, as shown in FIG4 . The overshoot protection circuit 100 is applied to a power module and includes an overshoot protection module 110 and a selection module 120 , wherein:

[0051] The overshoot protection module 110 is used to detect the output voltage of the power module and output a control signal when the output voltage is outside a preset voltage range;

[0052] The selection module 120 is used to charge or discharge the parasitic capacitance of the first power tube Q1 in the power module according to the control signal when the output voltage is outside the preset voltage range, so that the power module output optimizes the peak voltage caused by load switching.

[0053] In an embodiment of the present invention, an overshoot protection circuit 100 is applied to a power supply module, which includes an LDO, a charge pump, a DC-DC, etc. The overshoot protection circuit can be applied to the peak voltage problem caused by load switching in the above-mentioned power supply module. The power supply module can be determined according to actual conditions. In an embodiment of the present invention, the voltage regulator 200 is used as an example of the power supply module for illustration.

[0054] In an embodiment of the present invention, the overshoot protection circuit 100 includes an overshoot protection module 110 and a selection module 120. The input end of the overshoot protection module 110 is connected to an output end of the voltage regulator 200, the output end of the overshoot protection module 110 is connected to the input end of the selection module 120, and the output end of the selection module 120 is connected to an input end of the voltage regulator 200.

[0055] During the operation of the overshoot protection circuit 100, the voltage regulator 200 outputs an output voltage during operation. Generally, the output voltage is an analog voltage signal. After the overshoot protection module 110 receives the output voltage signal, when the voltage regulator 200 generates a large peak voltage (the peak voltage here includes overshoot voltage and undershoot voltage), the overshoot protection circuit 100 is triggered to start working. According to the type of peak voltage, the corresponding switching tube is turned on to generate a charging and discharging path for the gate capacitance of the power tube, thereby compensating for the response rate of the power tube when the load current is quickly switched.

[0056] Specifically, the overshoot protection module 110 determines whether the output voltage is within a preset voltage range. The preset voltage range is the voltage range in which the output voltage is stable, that is, the range of the output voltage of the voltage regulator 200 when no overvoltage or undervoltage occurs. The specific value can be determined according to actual conditions. The embodiment of the present invention can be determined according to actual conditions.

[0057] When the load current of the voltage stabilizer 200 changes suddenly, from light load to heavy load or from heavy load to light load, the output voltage of the voltage stabilizer 200 will also change suddenly. If the overshoot detection module 110 determines that the output voltage is outside the preset voltage range, it means that the voltage stabilizer 200 has an overvoltage or undervoltage condition. In order to avoid the overshoot problem, the overshoot protection module 110 outputs a control signal in this case. Generally, the control signal is a digital signal with a value of 0 or 1, which can be determined according to actual conditions. The embodiment of the present invention does not make specific limitations on this.

[0058] It should be noted that the overshoot protection module 110 in the embodiment of the present invention can be a circuit composed of resistors, capacitors, etc. according to certain rules, or it can be implemented by programming a processor. The specific method can be determined according to actual conditions, and the embodiment of the present invention does not make any specific limitations on this.

[0059] When the selection module 120 also detects that the output voltage is outside the preset voltage range, the selection module 120 receives the control signal and controls the first power tube Q1 according to the control signal, providing an additional charging and discharging path to enhance the response rate of the first power tube Q1, thereby preventing the spike voltage problem generated by the LDO during the load switching process (the spike voltage here includes overshoot voltage and undershoot voltage), and can improve or optimize the transient characteristics of the regulator 200 circuit.

[0060] Generally, the optimized load voltage is within the preset voltage range, and voltage overshoot does not occur. In the embodiment of the present invention, the selection module 120 can be a circuit composed of resistors, capacitors, etc. according to certain rules, or can be implemented by programming a processor. The specific method can be determined according to actual conditions and is not specifically limited in the embodiment of the present invention.

[0061] The present invention successfully controls the peak voltage of the low-dropout linear regulator 200 caused by load switching within the threshold range of the LDO output stable voltage, thereby avoiding the generation of a large peak voltage that affects the performance of the chip.

[0062] The present invention proposes an overshoot protection circuit 100. When the output voltage of a power module is outside a preset voltage range, an overshoot protection module 110 generates a control signal based on the LDO output voltage. A selection module 120 controls the charging or discharging of the parasitic capacitance of a first power transistor Q1 in the power module based on the control signal. The overshoot protection circuit improves the transient performance of the first power transistor by providing an additional charging and discharging path, thereby compensating for the problem that the power transistor cannot respond in time due to rapid switching of the load current.

[0063] The optimized load voltage ultimately output by the power module of the embodiment of the present invention is within a preset voltage range. The present invention successfully limits the overshoot voltage and undershoot voltage generated by the power module output at the moment of load switching to within a given voltage range. The magnitude of the overshoot voltage and undershoot voltage can be controlled at any moment of load switching of the power module to avoid overshoot; and there is no need to significantly increase the chip area.

[0064] In some embodiments, the preset voltage range includes a preset maximum voltage threshold and a preset minimum voltage threshold, and the control signal includes a first control signal and a second control signal, wherein:

[0065] The overshoot protection module 110 is configured to output the first control signal when the output voltage is greater than the preset maximum voltage threshold, and output the second control signal when the output voltage is less than the preset minimum voltage threshold;

[0066] The selection module 120 is configured to control the charging of the parasitic capacitor according to the first control signal, and to control the discharging of the parasitic capacitor according to the second control signal.

[0067] In the embodiment of the present invention, the two endpoints of the preset voltage range are a preset maximum voltage threshold and a preset minimum voltage threshold, respectively denoted by VREFMAX and VREFMIN. The preset maximum voltage threshold represents the maximum value that the output voltage of the voltage regulator 200 can reach when the voltage regulator 200 is operating normally, and the preset minimum voltage threshold represents the lowest value that the output voltage can reach when the voltage regulator 200 is operating normally. The specific values ​​can be determined according to actual conditions, and the embodiment of the present invention does not impose any specific limitation on this.

[0068] After receiving the output voltage, the overshoot protection circuit 100 compares the output voltage with a preset maximum voltage threshold. If the output voltage is greater than the preset maximum voltage threshold, indicating that the voltage regulator 200 has an overvoltage condition, the overshoot protection circuit 100 outputs a first control signal. After receiving the first control signal, the selection module 120 controls the first power transistor Q1 to conduct, so that the parasitic capacitance in the first power transistor Q1 can be charged. When the voltage regulator 200 is overvoltage, the embodiment of the present invention charges the parasitic capacitance in the first power transistor Q1 to slow down the trend of the output voltage from continuing to increase, thereby alleviating the overvoltage condition of the voltage regulator 200.

[0069] If the output voltage of the voltage regulator 200 is less than the preset maximum voltage threshold, the output voltage is compared with a preset minimum voltage threshold. If the output voltage is less than the preset minimum voltage threshold, it indicates that the voltage regulator has an undervoltage condition. The overshoot protection module 110 then outputs a second control signal. After receiving the second control signal, the selection module 120 controls the first power transistor Q1 to conduct, thereby discharging the parasitic capacitance in the first power transistor Q1. When the voltage regulator 200 is undervoltage, the embodiment of the present invention discharges the parasitic capacitance in the first power transistor Q1, thereby slowing down the further decrease in the output voltage and alleviating the undervoltage condition of the voltage regulator 200.

[0070] If the output voltage is less than the preset maximum voltage threshold and greater than the preset minimum voltage threshold, it indicates that the voltage regulator is operating normally, and the overshoot protection module 110 is disconnected.

[0071] It should be noted that, in the embodiment of the present invention, the first power tube Q1 includes a triode and a MOS tube, which can be specifically determined according to the actual circuit and is not specifically limited in the embodiment of the present invention.

[0072] As an embodiment, the overshoot protection module 110 includes an overvoltage detection unit 111 and an undervoltage detection unit 112, wherein:

[0073] The overvoltage detection unit 111 includes a second power tube Q2, and the overvoltage detection unit 111 is used to output a first comparison signal when the output voltage is greater than a preset maximum voltage threshold, and control the second power tube Q2 to output a first control signal according to the first comparison signal;

[0074] The undervoltage detection unit 112 includes a third power transistor Q3. The undervoltage detection unit 112 is configured to output a second comparison signal when the output voltage is less than a preset minimum voltage threshold, and control the third power transistor Q3 to output a second control signal according to the second comparison signal.

[0075] In the embodiment of the present invention, the overshoot protection module 110 includes an overvoltage detection unit 111 and an undervoltage detection unit 112, wherein the output end of the power supply module is connected to the input end of the overvoltage detection unit 111 and the undervoltage detection unit 112, respectively. The output end of the overvoltage detection unit 111 and the output end of the undervoltage detection unit 112 are both used to output control signals. At most, only one of the overvoltage detection unit 111 and the undervoltage detection unit 112 can work at the same time.

[0076] The overvoltage detection unit 111 includes a second power tube Q2. The overvoltage detection unit 111 compares the output voltage with a preset maximum voltage threshold. If the output voltage is greater than the preset maximum voltage threshold, the overvoltage detection unit 111 outputs a first comparison signal and controls the conduction of the second power tube Q2 according to the first comparison signal, thereby outputting a first control signal with a value so that the selection module 120 performs a corresponding operation according to the first control signal; if the output voltage is less than the preset maximum voltage threshold, the first comparison signal with another value is output, and the second power tube Q2 is controlled to be turned off according to the first comparison signal, so that the entire overvoltage detection unit 111 is in a disconnected state.

[0077] The undervoltage detection unit 112 includes a third power tube Q3. The undervoltage detection unit 112 compares the output voltage with a preset minimum voltage threshold. If the output voltage is less than the preset minimum voltage threshold, the undervoltage detection unit 112 outputs a second comparison signal and controls the on or off state of the third power tube Q3 according to the second comparison signal, thereby outputting a second control signal with a certain value so that the selection module 120 performs a corresponding operation according to the second control signal. If the output voltage is greater than the preset minimum voltage threshold, the undervoltage detection unit 112 outputs a second comparison signal with another value and controls the third power tube Q3 to be turned on according to the second comparison signal, thereby putting the entire undervoltage detection unit 112 into a disconnected state.

[0078] It should be noted that, in the embodiment of the present invention, the overvoltage detection unit 111 and the undervoltage detection unit 112 can be circuits composed of resistors, capacitors, etc. according to certain rules, or can be implemented by programming a processor. The specific details can be determined according to actual conditions, and the embodiment of the present invention does not make specific limitations on this.

[0079] For example, the overvoltage detection unit 111 includes a first comparator 113, the input end of the first comparator 113 is used to connect to the output end of the power supply module, the output end of the first comparator 113 is connected to the control end of the second power tube Q2, the first connection end of the second power tube Q2 is used to connect to an external power supply, and the second connection end of the second power tube Q2 outputs the first control signal.

[0080] For example, the undervoltage detection unit 112 includes a second comparator 114, the input end of the second comparator 114 is used to connect the output end of the power module, the output end of the second comparator 114 is connected to the control end of the third power tube Q3, the first connection end of the third power tube Q3 is used to be grounded, and the second connection end of the third power tube Q3 outputs the second control signal.

[0081] It should be noted that the second power tube Q2 and the third power tube Q3 may be triodes or MOS tubes, which may be determined according to actual conditions and are not specifically limited in the embodiment of the present invention.

[0082] An embodiment of the present invention provides an overshoot protection module 110, as shown in Figure 5. In the embodiment of the present invention, the overvoltage detection unit 111 includes a first comparator 113 and a second power tube Q2. One input end of the first comparator 113 is used to connect to the output end of the power supply module, and the other input end of the first comparator 113 is connected to a first reference signal, which is a preset maximum voltage threshold. The output end of the first comparator 113 is connected to the control end of the second power tube Q2. The first connection end of the second power tube Q2 is used to connect to an external power supply, and the second connection end of the second power tube Q2 outputs a first control signal.

[0083] The undervoltage detection unit 112 includes a second comparator 114 and a third power tube Q3. One input end of the second comparator 114 is used to connect to the output end of the power module. The other input end of the second comparator 114 is connected to a second reference signal, which is a preset minimum voltage threshold. The output end of the second comparator 114 is connected to the control end of the second power tube Q2. The first connection end of the third power tube Q3 is used to be grounded, and the second connection end of the third power tube Q3 outputs the first control signal.

[0084] In the embodiment of the present invention, the second power tube Q2 is a PMOS tube, and the third power tube Q3 is an NMOS tube.

[0085] During the operation of the overshoot protection module 110, the first comparator 113 and the second comparator 114 receive the output voltage V OUT The first comparator 113 compares the output voltage with the preset maximum voltage threshold. When the output voltage V OUT When the voltage is greater than the preset maximum threshold VREFMAX, the first comparator 113 outputs a first comparison signal of 0, the second switch tube is turned on, and the first control signal GLITCH_OUT is pulled high, forming a parasitic capacitance C from the power supply to the second power tube Q2. POW,GS The first comparator 113 compares the output voltage with the preset minimum voltage threshold. OUT Less than the preset minimum voltage threshold V REFMINWhen the second comparator 114 outputs the second comparison signal of 1, the third switch tube is turned on, and the second control signal GLITCH_OUT is pulled low, forming the parasitic capacitance C of the second power tube Q2. POW,GS Discharge path to ground.

[0086] In some embodiments, the overshoot protection circuit 100 further includes a control module 130, wherein:

[0087] The control module 130 is configured to output a selection signal when the output voltage is outside the preset voltage range, so that the selection module 120 controls the output end of the overshoot protection module 110 to be connected to the first power transistor Q1 according to the selection signal.

[0088] An embodiment of the present invention provides a structure of an overshoot protection circuit 100, as shown in Figure 6, in which the output end of the control module 130 is connected to the control end of the selection module 120. When the control module 130 determines that the output voltage is outside the preset voltage range, the selection signal is output. Specifically, the control module 130 can determine whether the output voltage is outside the preset voltage range by matching the output voltage with the preset voltage range, or by receiving a certain indication signal. For example, receiving an indication signal of 0 indicates that the output voltage is within the preset voltage range, and receiving an indication signal of 1 indicates that the output voltage is outside the preset voltage range. The specific determination can be made based on actual conditions, and the embodiment of the present invention does not make any specific limitations on this.

[0089] When the output voltage is outside the preset voltage range, the control module 130 outputs a selection signal. After receiving the selection signal, the control end of the selection module 120 controls the output end of the overshoot protection module 110 to be connected to the first power tube Q1, so that the first power tube Q1 is taken over by the overshoot protection module 110 to achieve overvoltage or undervoltage adjustment.

[0090] It should be noted that, in the embodiment of the present invention, the control module 130 may be a circuit composed of resistors, capacitors, etc. according to certain rules, or it may be implemented by programming a processor. The specific method may be determined according to actual conditions, and the embodiment of the present invention does not make any specific limitation on this.

[0091] As an example, the control module 130 is configured to perform an XOR operation on the first comparison signal and the second comparison signal, and output the selection signal.

[0092] A circuit of a control module 130 provided by an embodiment of the present invention is shown in FIG7 . The two input terminals of the control module 130 respectively receive a first comparison signal and a second comparison signal, where the first comparison signal is represented by CMP1OUT and the second comparison signal is represented by CMP2OUT. An exclusive-OR operation is performed on the first comparison signal and the second comparison signal. When the first comparison signal and the second comparison signal are the same, a selection signal with a magnitude of 1 is output. When the first comparison signal and the second comparison signal are different, a selection signal with a magnitude of 0 is output. The selection signal is represented by GLITCH_ENP.

[0093] In the embodiment of the present invention, the control module 130 is an XNOR gate, and the first comparison signal and the second comparison signal are connected to two input terminals of the XNOR gate respectively.

[0094] It should be noted that the control module 130 further includes a filter network for filtering the selection signal before outputting it.

[0095] An overshoot protection circuit 100 provided by an embodiment of the present invention is applied to a voltage regulator circuit, as shown in FIG8 . The selection module 120 is a selector 2-1MUX. When the load current is stable, that is, when the output voltage of the voltage regulator is less than a preset maximum voltage threshold VREFMXA but greater than a preset minimum voltage threshold VREFMIN, the first comparator 113 outputs a first control signal of 1, and the second comparator 114 outputs a second control signal of 0. The control module 130 performs an exclusive-OR operation on the first control signal and the second control signal, outputting a selection signal GLITCH_ENP of 0. At this point, the selection module 1202-1MUX selects the error amplifier output to drive the first power transistor Q1 of the voltage regulator.

[0096] When the load current switches from heavy load to light load instantaneously, the first power tube Q1 does not have time to react, and the load capacitor CL starts to charge, resulting in the output voltage V OUT The voltage increases rapidly. When the output voltage of the voltage regulator is greater than the preset maximum voltage threshold VREFMAX, the first comparator 113 outputs a first comparison signal of 0, and the second comparator 114 also outputs a second comparison signal of 0. The control module 130 performs an exclusive-OR operation on the first control signal and the second control signal, and outputs a selection signal GLITCH_ENP of 1. The first power tube Q1 is turned on, and the error amplifier EA is turned off. At this time, the output GLITCH_OUT of the overshoot protection circuit 100 is connected to the gate of the first power tube Q1 through the 2-1MUX, and the power supply starts to supply the gate capacitor C of the first power tube Q1. GS,POW Charging causes the gate voltage to increase, causing the current I generated by the first power tube Q1 to DS,POW Reduce, suppress the increase of output voltage and prevent overshoot.

[0097] When the load current switches from light load to heavy load instantaneously, the first power tube Q1 does not have time to react, and the load capacitor CL begins to discharge, resulting in the output voltage V OUT The voltage is quickly pulled down. When the output voltage VOUT is less than the preset minimum voltage threshold VREFMIN, the first comparator 113 outputs a first comparison signal of 0, and the second comparator 114 outputs a second control signal of 1. GLITCH_ENP=1, the error amplifier EA is disconnected, and the overshoot protection circuit 100 works. At this time, the gate capacitance of the first power tube Q1 is quickly discharged, causing the first power tube Q1 to generate a current I DS,POW Increase, thereby suppressing the continued discharge of the load capacitor, the output voltage no longer decreases, and preventing overshoot.

[0098] As shown in Figure 9, when the output load switches from light load to heavy load after 64.04 ps, the output voltage of the LDO with overshoot protection circuit undershoots as low as 1.04V at the load switching moment, while the output voltage of the LDO without overshoot protection circuit undershoots as low as 410mV at the load switching moment.

[0099] As shown in Figure 10, when the output load switches from heavy load to light load after 64.04 ps, the LDO with overshoot protection circuit generates a maximum overshoot voltage of 2V at the load switching moment, while the LDO without overshoot protection circuit generates a maximum overshoot voltage of 2.79V at the load switching moment.

[0100] It should be noted that the bottom lines in FIG9 and FIG10 both represent current signals.

[0101] An embodiment of the present invention further provides a voltage stabilizer 200 , which includes the above-mentioned overcharge protection circuit 100 . The overcharge protection circuit is applied to the voltage stabilizer 200 , and its specific connection method can be referred to FIG8 .

[0102] An embodiment of the present invention further provides a chip, which includes the overcharge protection circuit 100 described above, or the voltage regulator 200 described above. The chip (Integrated Circuit, IC) can be, but is not limited to, a SOC (System on Chip) chip or a SIP (System in Package) chip.

[0103] An embodiment of the present invention provides a structure of an electronic device, which includes a device body and an overcharge protection circuit 100, a voltage regulator 200, or a chip as described above, which are provided in the device body. The electronic device can be, but is not limited to, a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a car charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a stylus, a true wireless headset, a car central console, a car, a smart wearable device, a mobile terminal, and a smart home device. Smart wearable devices include, but are not limited to, smart watches, smart bracelets, and cervical massagers. Mobile terminals include, but are not limited to, smartphones, laptops, tablets, and POS (Point of Sales Terminal) machines. Smart home devices include, but are not limited to, smart sockets, smart rice cookers, smart sweepers, and smart lights.

[0104] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0105] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. An overshoot protection circuit, characterized in that: The overshoot protection circuit is applied to a power supply module, and the overshoot protection circuit comprises an overshoot protection module and a selection module, wherein: The overshoot protection module is used to detect the output voltage of the power module and output a control signal when the output voltage is outside a preset voltage range; The selection module is used to charge or discharge the parasitic capacitance of the first power tube in the power module according to the control signal when the output voltage is outside the preset voltage range, so that the power module optimizes the peak voltage caused by load switching.

2. The overshoot protection circuit according to claim 1, characterized in that: The preset voltage range includes a preset maximum voltage threshold and a preset minimum voltage threshold, and the control signal includes a first control signal and a second control signal, wherein: The overshoot protection module is used to output the first control signal when the output voltage is greater than the preset maximum voltage threshold, and output the second control signal when the output voltage is less than the preset minimum voltage threshold; The selection module is used to control the charging of the parasitic capacitor according to the first control signal, and to control the discharging of the parasitic capacitor according to the second control signal.

3. The overshoot protection circuit according to claim 1, characterized in that: The overshoot protection module includes an overvoltage detection unit and an undervoltage detection unit, wherein: The overvoltage detection unit includes a second power tube, and the overvoltage detection unit is used to output a first comparison signal when the output voltage is greater than a preset maximum voltage threshold, and control the second power tube to output a first control signal according to the first comparison signal; The undervoltage detection unit includes a third power tube, and the undervoltage detection unit is used to output a second comparison signal when the output voltage is less than a preset minimum voltage threshold, and control the third power tube to output a second control signal according to the second comparison signal.

4. The overshoot protection circuit according to claim 3, characterized in that: The overvoltage detection unit includes a first comparator, the input end of the first comparator is used to connect to the output end of the power module, the output end of the first comparator is connected to the second power tube, the second power tube is used to connect to an external power supply, and the second power tube outputs the first control signal.

5. The overshoot protection circuit according to claim 3, characterized in that: The undervoltage detection unit includes a second comparator, the input end of the second comparator is used to connect the output end of the power module, the output end of the second comparator is connected to the third power tube, the third power tube is used to be grounded, and the third power tube outputs the second control signal.

6. The overshoot protection circuit according to any one of claims 1 to 5, characterized in that: The overshoot protection circuit further includes a control module, wherein: The control module is used for outputting a selection signal when the output voltage is outside the preset voltage range, so that the selection module controls the output end of the overshoot protection module to be connected to the first power tube according to the selection signal.

7. The overshoot protection circuit according to claim 6, characterized in that: The control module is used for performing an XOR operation on the first comparison signal and the second comparison signal, and outputting the selection signal.

8. A voltage stabilizer, characterized in that: The overshoot protection circuit as claimed in any one of claims 1 to 7 is applied to the voltage regulator.

9. A chip, characterized in that: It comprises the overshoot protection circuit as claimed in any one of claims 1 to 7, or the voltage regulator as claimed in claim 8.

10. An electronic device, characterized in that: include: The overshoot protection circuit as claimed in any one of claims 1 to 7; or, a voltage stabilizer as claimed in claim 8; Or, the chip as claimed in claim 9.

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