CN-122026268-A - Overvoltage protection circuit of power management chip and power management chip

CN122026268ACN 122026268 ACN122026268 ACN 122026268ACN-122026268-A

Abstract

The application relates to an overvoltage protection circuit of a power management chip and the power management chip, which comprises a voltage comparison unit, a current mirror unit, a hysteresis comparison and shaping unit, an internal protection signal and an output driving unit, wherein the input end of the voltage comparison unit is respectively connected with a voltage feedback terminal and a reference voltage terminal, a first current signal is generated according to the comparison result of feedback voltage and reference voltage, the current mirror unit mirrors the first current signal to a second output branch, generates a second current signal and a corresponding voltage signal, the hysteresis comparison and shaping unit performs hysteresis comparison and waveform shaping on the voltage signal and outputs the internal protection signal, the output driving unit performs driving enhancement on the internal protection signal to obtain a final overvoltage protection control signal, and then a negative feedback unit introduces negative feedback according to the state of the internal protection signal or the overvoltage protection control signal to adjust the triggering and recovery of the overvoltage protection circuit. Therefore, the problems of poor anti-interference capability, insufficient stability, lack of self-adaptive capability and the like of an overvoltage protection circuit in the related technology are solved.

Inventors

SONG SHUTAO
GUO YUHUI
YUAN SONG
ZHANG SHUYANG
Che Luqiang
LIN LIXIN
XU QING

Assignees

奇瑞汽车股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260112

Claims (10)

1. An overvoltage protection circuit of a power management chip, wherein the overvoltage protection circuit of the power management chip comprises a voltage input terminal, a reference voltage terminal, a voltage feedback terminal and an overvoltage protection signal output terminal, and the overvoltage protection circuit comprises: The first input end of the voltage comparison unit is connected with the voltage feedback terminal, the second input end of the voltage comparison unit is connected with the reference voltage terminal, and the voltage comparison unit is used for generating a first current signal in a first output branch of the voltage comparison unit according to the comparison result of the feedback voltage of the voltage feedback terminal and the reference voltage of the reference voltage terminal; the first input end of the current mirror unit is connected with the output end of the voltage comparison unit and is used for mirroring the first current signal to a second output branch in the current mirror unit and generating a second current signal corresponding to the first current signal and a voltage signal corresponding to the second current signal in the second output branch; The input end of the hysteresis comparison and shaping unit is connected with the output end of the current mirror unit and is used for performing hysteresis comparison and waveform shaping on the voltage signal corresponding to the second current signal and outputting an internal protection signal; the input end of the output driving unit is connected with the output end of the hysteresis comparison and shaping unit and is used for driving and enhancing the internal protection signal to obtain a final overvoltage protection control signal and outputting the final overvoltage protection control signal to the overvoltage protection signal output terminal; and the output end of the negative feedback unit is connected with the voltage comparison unit and the bias node of the current mirror unit, and is used for introducing negative feedback according to the state of the internal protection signal or the overvoltage protection control signal and adjusting the triggering and recovery of the overvoltage protection circuit.
2. The overvoltage protection circuit of a power management chip according to claim 1, wherein the hysteresis comparison and shaping unit comprises: And the Schmitt trigger is used for separating the rising trigger threshold value and the falling recovery threshold value of the overvoltage protection signal to form a voltage hysteresis zone.
3. The overvoltage protection circuit of a power management chip according to claim 1, wherein the current mirror unit comprises: and one end of the filter capacitor is connected with the output end of the current mirror image unit, and the other end of the filter capacitor is grounded and used for filtering high-frequency noise in the second current signal.
4. The overvoltage protection circuit of a power management chip according to claim 1, wherein the voltage comparison unit includes: The first PMOS tube and the second PMOS tube are connected with the voltage input terminal together, the grid electrode of the first PMOS tube is connected with the reference voltage terminal, and the grid electrode of the second PMOS tube is connected with the voltage feedback terminal; The drain electrode of the first NMOS tube is connected with the drain electrode of the first PMOS tube, the drain electrode of the second NMOS tube is connected with the drain electrode of the second PMOS tube, the source electrode of the first NMOS tube is connected with the source electrode of the second NMOS tube, and the source electrodes are grounded through a constant current source, wherein the drain electrode of the first NMOS tube and the drain electrode of the second NMOS tube are output as the first current signal.
5. The overvoltage protection circuit of a power management chip according to claim 1 or 4, wherein the current mirror unit includes: The grid electrode of the third NMOS tube and the grid electrode of the fourth NMOS tube are connected with the drain electrodes of the first PMOS tube and the first NMOS tube, wherein the source electrodes of the third NMOS tube and the fourth NMOS tube are grounded, the drain electrode of the third NMOS tube forms the input end of the current mirror image unit, the drain electrode of the fourth NMOS tube forms the output end of the current mirror image unit, and meanwhile, the drain electrode of the fourth NMOS tube is connected with the input end of the hysteresis comparison and shaping unit.
6. The overvoltage protection circuit of a power management chip according to claim 1, wherein the negative feedback unit comprises: The feedback signal generation subunit is used for carrying out delay and inversion processing on the internal protection signal to generate a feedback control signal; and the feedback execution subunit is used for receiving the feedback control signal and connecting a conduction path of the feedback control signal to the voltage comparison unit or the current mirror unit so as to change the working state of the voltage comparison unit or the current mirror unit.
7. The overvoltage protection circuit of a power management chip of claim 6, wherein the feedback execution subunit comprises: And the grid electrode of the fifth NMOS tube receives the feedback control signal, the source electrode of the fifth NMOS tube is grounded, and the drain electrode of the fifth NMOS tube is connected with the output end of the voltage comparison unit or the first output branch of the voltage comparison unit.
8. The overvoltage protection circuit of claim 1, wherein the output driving unit is composed of an odd number of cascaded inverters for shaping and power enhancing the signal output from the hysteresis comparison and shaping unit.
9. The overvoltage protection circuit of a power management chip of claim 1, further comprising: And the bias voltage terminal is used for providing bias voltage for the PMOS tube in the voltage comparison unit, and the bias voltage is generated by the voltage input terminal and changes along with the voltage input terminal to provide bias for the PMOS tube in the voltage comparison unit.
10. A power management chip comprising an overvoltage protection circuit of the power management chip according to any one of claims 1-9.

Description

Overvoltage protection circuit of power management chip and power management chip Technical Field The present application relates to the field of integrated circuits, and in particular, to an overvoltage protection circuit of a power management chip and a power management chip. Background The overvoltage protection circuit is a critical safety module in a power management chip, and the working principle is that the input voltage is monitored in real time through a voltage detection unit and compared with a preset threshold value, when the input voltage exceeds the threshold value, the detection unit outputs a trigger signal to drive a MOSFET (Metal-Oxide-Semiconductor-Field-Effect Transistor) to rapidly cut off a main power supply loop, so that overvoltage energy is isolated or absorbed, the damage of a rear-end circuit is avoided, and the core flow is' monitoring-threshold value comparison-trigger protection action, so that the damage of a rear-end circuit due to overvoltage is prevented. In the related art, an overvoltage protection circuit generally includes a voltage detection unit, a comparison unit and an execution unit, where the voltage detection unit monitors an input voltage in real time and compares the input voltage with a preset fixed voltage threshold, and when the input voltage exceeds the fixed voltage threshold, the comparison unit outputs a trigger signal to control the execution unit to cut off a main power supply path. However, the method has the defects of (1) poor anti-interference capability, easy false triggering caused by voltage fluctuation and frequent switching of a main loop, (2) insufficient stability, namely voltage noise influence judgment in the power-on process, and (3) lack of self-adaptive capability, namely incapability of automatically recovering after protection, and need external intervention to be solved urgently. Disclosure of Invention The application provides an overvoltage protection circuit of a power management chip and the power management chip, which are used for solving the problems of poor anti-interference capability, insufficient stability, lack of self-adaptive capability and the like of the overvoltage protection circuit in the related technology. An embodiment of a first aspect of the present application provides an overvoltage protection circuit of a power management chip, where the overvoltage protection circuit of the power management chip includes a voltage input terminal, a reference voltage terminal, a voltage feedback terminal, and an overvoltage protection signal output terminal, and the overvoltage protection circuit includes: The first input end of the voltage comparison unit is connected with the voltage feedback terminal, the second input end of the voltage comparison unit is connected with the reference voltage terminal, and the voltage comparison unit is used for generating a first current signal in a first output branch of the voltage comparison unit according to the comparison result of the feedback voltage of the voltage feedback terminal and the reference voltage of the reference voltage terminal; the first input end of the current mirror unit is connected with the output end of the voltage comparison unit and is used for mirroring the first current signal to a second output branch in the current mirror unit and generating a second current signal corresponding to the first current signal and a voltage signal corresponding to the second current signal in the second output branch; The input end of the hysteresis comparison and shaping unit is connected with the output end of the current mirror unit and is used for performing hysteresis comparison and waveform shaping on the voltage signal corresponding to the second current signal and outputting an internal protection signal; the input end of the output driving unit is connected with the output end of the hysteresis comparison and shaping unit and is used for driving and enhancing the internal protection signal to obtain a final overvoltage protection control signal and outputting the final overvoltage protection control signal to the overvoltage protection signal output terminal; and the output end of the negative feedback unit is connected with the voltage comparison unit and the bias node of the current mirror unit, and is used for introducing negative feedback according to the state of the internal protection signal or the overvoltage protection control signal and adjusting the triggering and recovery of the overvoltage protection circuit. Further, in some embodiments, the hysteresis comparison and shaping unit comprises: And the Schmitt trigger is used for separating the rising trigger threshold value and the falling recovery threshold value of the overvoltage protection signal to form a voltage hysteresis zone. Further, in some embodiments, the current mirror unit includes: and one end of the filter capacitor is connected with the output end of the current mirror image unit, and t