Power failure detection circuit and electronic equipment
Through the circuit structure of the controllable voltage stabilization unit and switch tube, the problem of the power-down detection circuit being greatly affected by temperature is solved, high-precision power-down detection is achieved, and the backflow current is prevented, ensuring the reliability of the circuit.
Patent Information
- Application Number
- CN202422382967.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2034-09-27
AI Technical Summary
The existing power-down detection circuit is greatly affected by temperature and has low power-down detection accuracy.
The circuit structure of a controllable voltage stabilization unit and a switch tube is adopted, and the controllable voltage stabilization unit itself has small temperature characteristics, combined with the conduction and shutdown of the switch tube, the precise transmission of the power-down detection signal is achieved, and the backflow prevention module prevents damage to the circuit.
Ensure accurate transmission of power-down detection signals within a wide temperature range, improve the accuracy of power-down detection, and prevent damage to the circuit by backflow current.
Smart Images
Figure CN223217575U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power electronics technology, and in particular to a power failure detection circuit and electronic equipment. Background Art
[0002] As large electronic devices become increasingly versatile and feature-rich, the demand for their internal storage capabilities is increasing. In actual device operation, external power supply drops or even interruptions are inevitable. In these situations, if the device's CPU (Central Processing Unit) cannot be notified promptly to perform power-down hold operations, serious system errors may occur after the device restarts. Therefore, the design of power-down detection circuits is crucial for device system protection.
[0003] In the related art, existing power-off detection solutions are categorized into two types: isolated and non-isolated. The isolated solution uses an optocoupler and a transistor to transmit the power-off detection signal, while the non-isolated solution uses a voltage divider resistor and a transistor to transmit the power-off detection signal. However, in both solutions, the voltage is significantly affected by temperature, resulting in inaccurate power-off detection signal transmission and low power-off detection accuracy. Utility Model Content
[0004] The main purpose of this application is to provide a power-off detection circuit and electronic equipment, aiming to solve the problem that the existing power-off detection circuit is greatly affected by temperature and has low power-off detection accuracy.
[0005] To achieve the above objectives, the present application provides a power failure detection circuit, which includes:
[0006] a control module, wherein an input terminal of the control module is connected to an input power supply, and the control module includes a processor unit;
[0007] a power-off detection module, the power-off detection module comprising a controllable voltage stabilizing unit, a first switching tube, and a second switching tube, wherein a controlled end of the controllable voltage stabilizing unit is connected to the input power supply, a second end of the controllable voltage stabilizing unit is connected to the controlled end of the first switching tube, a first end of the controllable voltage stabilizing unit is grounded, a second end of the first switching tube is connected to a first output end of the control module, a first end of the first switching tube is respectively connected to the controlled end of the second switching tube and ground, a second end of the second switching tube is respectively connected to the second output end of the control module and the controlled end of the processor unit, and a first end of the second switching tube is grounded;
[0008] The power-off detection module is configured to output a power-off detection signal when the output voltage of the input power source meets a power-off condition, so that the processor unit of the control module performs a power-off holding operation based on the power-off detection signal.
[0009] In one embodiment, the power-off detection circuit further includes an anti-backflow module, wherein an input end of the anti-backflow module is connected to the input power supply, an output end of the anti-backflow module is respectively connected to an input end of the control module and a controlled end of the controllable voltage stabilizing unit, and a controlled end of the anti-backflow module is respectively connected to a first end of the first switching tube and a controlled end of the second switching tube;
[0010] The anti-backflow module is configured to perform an anti-backflow protection operation based on the anti-backflow driving signal output by the power-off detection module when the output voltage of the input power source meets a power-off condition.
[0011] In one embodiment, the backflow prevention module includes a third switch tube and a fourth switch tube;
[0012] The controlled end of the third switch tube is respectively connected to the first end of the first switch tube and the controlled end of the second switch tube, the first end of the third switch tube is respectively connected to the controlled end of the fourth switch tube and the input end of the control module, the second end of the third switch tube is grounded, the first end of the fourth switch tube is connected to the input power supply, and the second end of the fourth switch tube is connected to the input end of the control module.
[0013] In one embodiment, the control module also includes a voltage conversion unit; the input end of the voltage conversion unit is connected to the second end of the fourth switch tube, the first output end of the voltage conversion unit is connected to the second end of the first switch tube, and the second output end of the voltage conversion unit is respectively connected to the input end of the processor unit and the second end of the second switch tube.
[0014] In one embodiment, the voltage conversion unit includes a first voltage conversion unit and a second voltage conversion unit;
[0015] The input end of the first voltage conversion unit is connected to the second end of the fourth switch tube, the output end of the first voltage conversion unit is respectively connected to the input end of the second voltage conversion unit and the second end of the first switch tube, and the output end of the second voltage conversion unit is respectively connected to the input end of the processor unit and the second end of the second switch tube.
[0016] In one embodiment, the power-off detection circuit further includes a filter module, wherein a first end of the filter module is respectively connected to the second end of the fourth switch tube and the input end of the first voltage conversion unit, and a second end of the filter module is respectively connected to the second end of the third switch tube and ground;
[0017] The filtering module is used to filter the voltage output by the backflow prevention module.
[0018] In one embodiment, the power-off detection module further includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, and a second capacitor;
[0019] The second end of the first resistor is connected to the second end of the fourth switching transistor, the first end of the filtering module, and the input end of the first voltage conversion unit. The first end of the first resistor is respectively connected to the controlled end of the controllable voltage stabilizing unit and the second end of the second resistor. The first end of the second resistor is respectively connected to the first end of the controllable voltage stabilizing unit and the ground. The first end of the third resistor is connected to the second end of the controllable voltage stabilizing unit. The second end of the third resistor is respectively connected to the controlled end of the first switching transistor and the first end of the fourth resistor. The second end of the fourth resistor is respectively connected to the output end of the first voltage conversion unit and the second end of the first switching transistor. The second end of the fifth resistor is respectively connected to the first end of the first switching transistor, the controlled end of the third switching transistor, and the first end of the sixth resistor. The first end of the fifth resistor is grounded. The second end of the sixth resistor is respectively connected to the controlled end of the second switching transistor and the second end of the seventh resistor. The first end of the seventh resistor is respectively connected to the first end of the second switching transistor and the ground. The second end of the eighth resistor is connected to the output end of the second voltage conversion unit. The first end of the eighth resistor is respectively connected to the second end of the second switching transistor and the controlled end of the processor unit.
[0020] The second end of the first capacitor is respectively connected to the first end of the first resistor, the second end of the second resistor and the controlled end of the controllable voltage stabilizing unit, the first end of the first capacitor is respectively connected to the first end of the second resistor, the first end of the controllable voltage stabilizing unit and the ground, the second end of the second capacitor is respectively connected to the second end of the sixth resistor, the second end of the seventh resistor and the controlled end of the second switch tube, and the first end of the second capacitor is respectively connected to the first end of the seventh resistor, the first end of the second switch tube and the ground.
[0021] In one embodiment, the backflow prevention module further includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a third capacitor, a fourth capacitor, and a fifth capacitor;
[0022] The first end of the ninth resistor is respectively connected to the first end of the first switching transistor, the second end of the fifth resistor, and the first end of the sixth resistor; the second end of the ninth resistor is respectively connected to the controlled end of the third switching transistor and the first end of the tenth resistor; the second end of the tenth resistor is respectively connected to the second end of the third switching transistor and ground; the first end of the eleventh resistor is respectively connected to the controlled end of the fourth switching transistor and the second end of the twelfth resistor; the second end of the eleventh resistor is connected to the first end of the third switching transistor; and the first end of the twelfth resistor is respectively connected to the input end of the first voltage conversion unit and the second end of the fourth switching transistor;
[0023] The first end of the third capacitor is respectively connected to the second end of the ninth resistor, the first end of the tenth resistor, the controlled end of the third switch tube and the second end of the fourth capacitor; the second end of the third capacitor is respectively connected to the second end of the tenth resistor, the second end of the third switch tube and the ground; the first end of the fourth capacitor is respectively connected to the first end of the eleventh resistor, the second end of the twelfth resistor, the controlled end of the fourth switch tube and the second end of the fifth capacitor; the first end of the fifth capacitor is respectively connected to the second end of the fourth switch tube, the first end of the twelfth resistor and the input end of the first voltage conversion unit.
[0024] In one embodiment, the anti-backflow module further includes a voltage stabilizing diode;
[0025] The first end of the voltage-stabilizing diode is respectively connected to the first end of the twelfth resistor, the input end of the first voltage conversion unit, the first end of the fifth capacitor, and the second end of the fourth switch tube, and the second end of the voltage-stabilizing diode is respectively connected to the first end of the eleventh resistor, the second end of the twelfth resistor, the first end of the fourth capacitor, the second end of the fifth capacitor, and the controlled end of the fourth switch tube.
[0026] In addition, to achieve the above-mentioned purpose, the present application also provides an electronic device, which includes the above-mentioned power-off detection circuit.
[0027] The power-off detection circuit provided in the present application includes a control module and a power-off detection module. The input end of the control module is connected to the input power supply, and the control module includes a processor unit; the power-off detection module includes a controllable voltage stabilizing unit, a first switch tube and a second switch tube, the controlled end of the controllable voltage stabilizing unit is connected to the input power supply, the second end of the controllable voltage stabilizing unit is connected to the controlled end of the first switch tube, the first end of the controllable voltage stabilizing unit is grounded, the second end of the first switch tube is connected to the first output end of the control module, the first end of the first switch tube is respectively connected to the controlled end of the second switch tube and the ground, the second end of the second switch tube is respectively connected to the second output end of the control module and the controlled end of the processor unit, and the first end of the second switch tube is grounded; the power-off detection module is used to output a power-off detection signal when the voltage of the input power supply meets the power-off condition, so that the processor unit of the control module performs a power-off holding operation based on the power-off detection signal. This application adopts a circuit structure of a controllable voltage stabilizing unit and a switching tube to realize the transmission of the power-off detection signal. Due to the temperature characteristics of the controllable voltage stabilizing unit itself, its voltage is little affected by temperature, which can ensure the accurate transmission of the power-off detection signal in a wider temperature range, thereby improving the accuracy of power-off detection. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.
[0029] Figure 1 This is a schematic structural diagram of an embodiment of a power-off detection circuit provided by the present application;
[0030] Figure 2 This is a schematic structural diagram of an embodiment of a power-off detection circuit provided by the present application;
[0031] Figure 3 This is a schematic structural diagram of an embodiment of a power-off detection circuit provided by the present application;
[0032] Figure 4 This is a schematic structural diagram of an embodiment of a power-off detection circuit provided by the present application;
[0033] Figure 5 This is a schematic structural diagram of an embodiment of a power-off detection circuit provided by the present application;
[0034] Figure 6 This is a schematic structural diagram of an embodiment of a power-off detection circuit provided by the present application;
[0035] Figure 7This is a schematic diagram of the power-on and power-off process of the power-off detection circuit provided in this application.
[0036] Description of Figure Numbers:
[0037] 100, power-off detection circuit; 10, control module; 11, processor unit; 12, voltage conversion unit; 121, first voltage conversion unit; 122, second voltage conversion unit; 20, power-off detection module; 30, input power supply; 40, backflow prevention module; 50, filter module; R1-R12, first resistor to twelfth resistor; Q1, controllable voltage stabilization unit; Q2-Q5, first switch tube to fourth switch tube; Q6, voltage regulator diode; C1-C6, first capacitor to sixth capacitor; PWR-EN, backflow prevention drive signal; PWR-DET, power-off detection signal; 24V_IN, 24V input voltage; 24V_OUT, 24V output voltage; 5V_IN, 5V input voltage; VDD-MCU, energy storage voltage.
[0038] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0039] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.
[0040] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.
[0041] In addition, in the embodiments of the present application, descriptions such as "first" and "second" are only for descriptive purposes and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the embodiments of the present application, the meaning of "plurality" is at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.
[0042] In the embodiments of the present application, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal connection between two elements or the interaction between two elements, unless otherwise specified. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.
[0043] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the embodiments of the present application.
[0044] In order to better understand the above technical solution, the above technical solution is described in detail below with reference to the accompanying drawings.
[0045] The increasing use and functionality of large electronic devices are driving demand for their internal storage capabilities. In actual device operation, these devices inevitably experience power outages or even power interruptions. If the device's CPU (Central Processing Unit) cannot be notified promptly to perform a power-down hold, serious system errors may occur after the device restarts. Therefore, the design of power-down detection circuits is crucial for device system protection.
[0046] Existing power-off detection solutions are categorized into two types: isolated and non-isolated. The isolated solution uses an optocoupler and a transistor to transmit the power-off detection signal, while the non-isolated solution uses a voltage divider resistor and a transistor to transmit the power-off detection signal. However, in both solutions, the voltage is significantly affected by temperature, resulting in inaccurate power-off detection signal transmission and low power-off detection accuracy.
[0047] In view of this, in order to solve the problems in the existing power-off detection circuit that the voltage is greatly affected by temperature, the power-off detection signal is not accurately transmitted, and the power-off detection accuracy is low, the present application provides a power-off detection circuit and electronic equipment.
[0048] In one embodiment of the present application, Figure 1As shown, the present application provides a power-off detection circuit 100, which includes a control module 10 and a power-off detection module 20. The input end of the control module 10 is connected to the input power supply 30, and the control module 10 includes a processor unit 11; the power-off detection module 20 includes a controllable voltage stabilizing unit Q1, a first switch tube Q2, and a second switch tube Q3. The controlled end of the controllable voltage stabilizing unit Q1 is connected to the input power supply 30, the second end of the controllable voltage stabilizing unit Q1 is connected to the controlled end of the first switch tube Q2, the first end of the controllable voltage stabilizing unit Q1 is grounded, the second end of the first switch tube Q2 is connected to the first output end of the control module 10, the first end of the first switch tube Q2 is respectively connected to the controlled end of the second switch tube Q3 and the ground, the second end of the second switch tube Q3 is respectively connected to the second output end of the control module 10 and the controlled end of the processor unit 11, and the first end of the second switch tube Q3 is grounded. The power failure detection module 20 is configured to output a power failure detection signal PWR-DET when the output voltage of the input power supply 30 meets the power failure condition, so that the processor unit 11 of the control module 10 performs a power failure holding operation based on the power failure detection signal PWR-DET.
[0049] In this embodiment, the controllable voltage stabilizing unit Q1 is a voltage stabilizing device that is less affected by temperature, such as the controllable precision voltage stabilizing power supply TL431; the first switch tube Q2 and the second switch tube Q3 are devices with switching functions, such as the first switch tube Q2 is a PMOS tube and the second switch tube Q3 is an NPN transistor; the processor unit 11 is a chip processor with data processing capabilities, such as an MCU or an FPGA; the power-off detection signal PWR-DET is a voltage signal or a level signal that drives the processor unit 11 to perform a power-off retention operation, and the power-off condition refers to the minimum output voltage of the input power supply 30 when driving the processor unit 11 to perform the power-off retention operation.
[0050] Specifically, when the output voltage of the input power supply 30 is operating normally or the system is powered on, as the voltage increases, on the one hand, the controllable voltage stabilizing unit Q1 is turned on, and the first switch tube Q2 and the second switch tube Q3 are subsequently turned on; on the other hand, the processor unit 11 of the control module 10 is operating normally. At this time, the entire power-off holding circuit 100 is in a non-power-off working state, the voltage at the second end of the second switch tube Q3 is relatively low, the power-off detection signal PWR-DET is a low-level signal, and the processor unit 11 does not perform the power-off holding operation.
[0051] When a power outage occurs due to a drop or interruption of the input power supply 30 or a system power-off shutdown, as the output voltage decreases, if the output voltage of the input power supply 30 drops to meet the power-off condition, the controllable voltage stabilizing unit Q1 is turned off, and the first switch tube Q2 and the second switch tube Q3 are subsequently turned off. At this time, the voltage at the second end of the second switch tube Q3 is relatively high, and the power-off detection signal PWR-DET is a high-level signal, thereby notifying the processor unit 11 to perform a power-off holding operation.
[0052] The technical solution provided in this embodiment utilizes a circuit structure comprising a controllable voltage stabilizing unit Q1, a first switching transistor Q2, and a second switching transistor Q3 to implement the transmission of the power-failure detection signal PWR-DET. Due to the temperature characteristics of the controllable voltage stabilizing unit Q1, its voltage is minimally affected by temperature. This ensures accurate transmission of the power-failure detection signal over a wide temperature range, thereby improving the accuracy of power-failure detection.
[0053] In one embodiment of the present application, Figure 2 As shown, the power-off detection circuit 100 further includes an anti-backflow module 40. The input end of the anti-backflow module 40 is connected to the input power supply 30, and the output end of the anti-backflow module 40 is respectively connected to the input end of the control module 10 and the controlled end of the controllable voltage stabilizing unit Q1. The controlled end of the anti-backflow module 40 is respectively connected to the first end of the first switch tube Q2 and the controlled end of the second switch tube Q3. The anti-backflow module 40 is configured to perform an anti-backflow protection operation based on the anti-backflow drive signal PWR-EN output by the power-off detection module 20 when the output voltage of the input power supply 30 meets the power-off condition.
[0054] In this embodiment, reverse voltage protection is a circuit protection feature. When the power supply in a circuit is connected in reverse, current reverses, potentially damaging the circuit. Backflow protection is a protective measure designed to prevent this reverse current from damaging the circuit. The backflow protection drive signal PWR-EN is a voltage signal or level signal that drives the backflow protection module 40 to perform the backflow protection operation.
[0055] Specifically, when the output voltage of the input power supply 30 is working normally or the system is powered on, as the output voltage increases, the controllable voltage stabilizing unit Q1 is turned on, and the first switch tube Q2 is then turned on. At this time, the voltage at the first end of the first switch tube Q2 is higher, and the anti-backflow drive signal PWR-EN is a high-level signal, thereby driving the anti-backflow module 40 to enter a normal working state.
[0056] When the input power supply 30 drops, is interrupted, or the system is powered off and shuts down, causing a power outage, as the output voltage decreases, if the output voltage of the input power supply 30 meets the power-off condition, the controllable voltage stabilizing unit Q1 is turned off, and the first switch tube Q2 is then turned off. At this time, the voltage at the first end of the first switch tube Q2 is low, and the anti-backflow drive signal PWR-EN is a low-level signal, thereby driving the anti-backflow module 40 to perform the anti-backflow protection operation.
[0057] In the technical solution provided by this embodiment, by providing the anti-backflow module 40, it is possible to prevent the backflow current from causing damage to the circuit.
[0058] In one embodiment of the present application, Figure 2 As shown, the backflow prevention module 40 includes a third switch tube Q4 and a fourth switch tube Q5; the controlled end of the third switch tube Q4 is respectively connected to the first end of the first switch tube Q2 and the controlled end of the second switch tube Q3, the first end of the third switch tube Q4 is respectively connected to the controlled end of the fourth switch tube Q5 and the input end of the control module 10, the second end of the third switch tube Q4 is grounded, the first end of the fourth switch tube Q5 is connected to the input power supply 30, and the second end of the fourth switch tube Q5 is connected to the input end of the control module 10.
[0059] In this embodiment, the third switch tube Q4 and the fourth switch tube Q5 are devices with switching functions. For example, the third switch tube Q4 is an NPN transistor, and the fourth switch tube Q5 is a PMOS transistor.
[0060] Specifically, when the output voltage of the input power supply 30 is working normally or the system is powered on, as the output voltage increases, the controllable voltage stabilizing unit Q1 is turned on, and the first switch tube Q2 is then turned on. At this time, the voltage at the first end of the first switch tube Q2 is high, and the anti-backflow drive signal PWR-EN is a high-level signal, which in turn drives the third switch tube Q4 to turn on, and the fourth switch tube Q5 is then turned on, and the anti-backflow module 40 enters normal working state.
[0061] When the input power supply 30 drops, is interrupted, or the system is powered off and shuts down, causing a power outage, as the output voltage decreases, if the output voltage of the input power supply 30 meets the power-off condition, the controllable voltage stabilizing unit Q1 is turned off, and the first switch tube Q2 is subsequently turned off. At this time, the voltage at the first end of the first switch tube Q2 is low, and the anti-backflow drive signal PWR-EN is a low-level signal, which in turn drives the third switch tube Q4 to turn off, and the fourth switch tube Q5 is subsequently turned off, and the anti-backflow module 40 performs the anti-backflow protection operation.
[0062] In the technical solution provided in this embodiment, the anti-backflow module 40 is turned on and off by the third switch tube Q4 and the fourth switch tube Q5, thereby realizing the anti-backflow protection of the power-off detection circuit 100 and effectively preventing the backflow current from damaging the power-off detection circuit 100.
[0063] In one embodiment of the present application, Figure 3 As shown, the control module 10 also includes a voltage conversion unit 12; the input end of the voltage conversion unit 12 is connected to the second end of the fourth switch tube Q5, the first output end of the voltage conversion unit 12 is connected to the second end of the first switch tube Q2, and the second output end of the voltage conversion unit 12 is respectively connected to the input end of the processor unit 11 and the second end of the second switch tube Q3.
[0064] In this embodiment, the voltage conversion unit 12 is a circuit or device that converts a high voltage into a low voltage, such as a BUCK circuit or a BUCK chip.
[0065] Specifically, when the output voltage of the input power supply 30 is working normally or the system is powered on, the large voltage output by the anti-backflow module 40 is converted into a small voltage through the voltage conversion unit 12. The converted voltage is output to the processor unit 11 on the one hand to enable the processor unit 11 to work normally; on the other hand, it is output to the power-off detection module 20 to enable the power-off detection module 20 to work normally.
[0066] In the technical solution provided by this embodiment, the voltage conversion unit 12 is used to realize voltage conversion, thereby ensuring the normal operation of the processor unit 11 and the power-off detection module 20 .
[0067] In one embodiment of the present application, Figure 3 As shown, the voltage conversion unit 12 includes a first voltage conversion unit 121 and a second voltage conversion unit 122; the input end of the first voltage conversion unit 121 is connected to the second end of the fourth switch tube Q5, the output end of the first voltage conversion unit 121 is respectively connected to the input end of the second voltage conversion unit 122 and the second end of the first switch tube Q2, and the output end of the second voltage conversion unit 122 is respectively connected to the input end of the processor unit 11 and the second end of the second switch tube Q3.
[0068] Specifically, when the output voltage of the input power supply 30 is working normally or the system is powered on, the large voltage output by the anti-backflow module 40 is first converted into a small voltage by the first voltage conversion unit 121. The voltage converted by the first voltage conversion unit 121 ensures the normal operation of the power-off detection module 20 on the one hand, and is output to the second voltage conversion unit 122 for secondary voltage conversion on the other hand. The voltage secondary converted by the second voltage conversion unit 122 is output to the processor unit 11 on the one hand to enable the processor unit to work normally, and is also output to the component loss detection module 20 on the other hand, ensuring the normal operation of the power-off detection module 20.
[0069] In the technical solution provided by this embodiment, two-level conversion of voltage magnitude is achieved through the first voltage conversion unit 121 and the second voltage conversion unit 122 , thereby ensuring the normal operation of the processor unit 11 and the power-off detection module 20 .
[0070] In one embodiment of the present application, Figure 4 As shown, the power-off detection circuit 100 also includes a filter module 50, the first end of the filter module 50 is respectively connected to the second end of the fourth switch tube Q5 and the input end of the first voltage conversion unit 121, and the second end of the filter module 50 is respectively connected to the second end of the third switch tube Q4 and the ground; the filter module 50 is used to filter the voltage output by the anti-backflow module 40.
[0071] In this embodiment, the filter module 50 is a circuit or device that filters the voltage output by the anti-backflow module 40 to ensure that the output voltage of the anti-backflow module 40 is output efficiently and smoothly. For example, the filter module 50 can be a filter capacitor.
[0072] Specifically, the voltage output by the backflow prevention module 40 is filtered by the filter module 50 , and the voltage after filtering by the filter module 50 is then output to the control module 10 and the power failure detection module 20 .
[0073] In the technical solution provided by this embodiment, the filtering module 50 is provided to filter the voltage output by the anti-backflow module 40 , thereby ensuring that the voltage output by the anti-backflow module 40 is stable, efficient and smooth.
[0074] In one embodiment of the present application, Figure 5As shown, the power-off detection module 20 also includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first capacitor C1 and a second capacitor C2; the second end of the first resistor R1 is connected to the second end of the fourth switch tube Q5, the first end of the filter module 50 and the input end of the first voltage conversion unit 121, the first end of the first resistor R1 is respectively connected to the controlled end of the controllable voltage stabilizing unit Q1 and the second end of the second resistor R2, the first end of the second resistor R2 is respectively connected to the first end of the controllable voltage stabilizing unit Q1 and the ground, the first end of the third resistor R3 is connected to the second end of the controllable voltage stabilizing unit Q1, and the second end of the third resistor R3 is respectively connected to the controlled end of the first switch tube Q2. an end thereof and a first end of a fourth resistor R4 are connected, a second end of the fourth resistor R4 are respectively connected to the output end of the first voltage conversion unit 121 and the second end of the first switching tube Q2, a second end of a fifth resistor R5 are respectively connected to the first end of the first switching tube Q2, the controlled end of the third switching tube Q4, and the first end of a sixth resistor R6, a first end of the fifth resistor R5 is respectively connected to the controlled end of the second switching tube Q3 and the second end of a seventh resistor R7, a first end of the seventh resistor R7 is respectively connected to the first end of the second switching tube Q3 and ground, a second end of an eighth resistor R8 is connected to the output end of the second voltage conversion unit 122, and a first end of the eighth resistor R8 is respectively connected to the second end of the second switching tube Q3 and the controlled end of the processor unit 11;
[0075] The second end of the first capacitor C1 is respectively connected to the first end of the first resistor R1, the second end of the second resistor R2, and the controlled end of the controllable voltage stabilizing unit Q1. The first end of the first capacitor C1 is respectively connected to the first end of the second resistor R2, the first end of the controllable voltage stabilizing unit Q1, and ground. The second end of the second capacitor C2 is respectively connected to the second end of the sixth resistor R6, the second end of the seventh resistor R7, and the controlled end of the second switch tube Q3. The first end of the second capacitor C2 is respectively connected to the first end of the seventh resistor R7, the first end of the second switch tube Q3, and ground.
[0076] In the technical solution provided in this embodiment, by providing resistors and capacitors and other resistive and capacitive components, voltage division and filtering of the circuit are achieved, thereby ensuring the reliable conduction of the controllable voltage stabilizing unit Q1, the first switch tube Q2, and the second switch tube Q3 of the power-off detection module 20, ensuring the accuracy of the transmission of the power-off detection signal PWR-DET, and improving the accuracy of power-off detection.
[0077] In one embodiment of the present application, Figure 5 As shown, the anti-backflow module 40 further includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5;
[0078] A first end of a ninth resistor R9 is respectively connected to the first end of the first switching transistor Q2, the second end of the fifth resistor R5, and the first end of the sixth resistor R6. A second end of the ninth resistor R9 is respectively connected to the controlled end of the third switching transistor Q4 and the first end of the tenth resistor R10. A second end of the tenth resistor R10 is respectively connected to the second end of the third switching transistor Q4 and ground. A first end of an eleventh resistor R11 is respectively connected to the controlled end of the fourth switching transistor Q5 and the second end of the twelfth resistor R12. A second end of the eleventh resistor R11 is connected to the first end of the third switching transistor Q4. A first end of the twelfth resistor R12 is respectively connected to the input end of the first voltage conversion unit 121 and the second end of the fourth switching transistor Q5.
[0079] A first end of the third capacitor C3 is respectively connected to the second end of the ninth resistor R9, the first end of the tenth resistor R10, the controlled end of the third switch tube Q4, and the second end of the fourth capacitor C4. A second end of the third capacitor C3 is respectively connected to the second end of the tenth resistor R10, the second end of the third switch tube Q4, and ground. A first end of the fourth capacitor C4 is respectively connected to the first end of the eleventh resistor R11, the second end of the twelfth resistor R12, the controlled end of the fourth switch tube Q5, and the second end of the fifth capacitor C5. A first end of the fifth capacitor C5 is respectively connected to the second end of the fourth switch tube Q5, the first end of the twelfth resistor R12, and the input end of the first voltage conversion unit 121.
[0080] In the technical solution provided in this embodiment, by setting resistors, capacitors and other resistive and capacitive components, the circuit voltage division and filtering are realized, the reliable conduction of the third switch tube Q4 and the fourth switch tube Q5 of the anti-backflow module 20 is ensured, the accurate transmission of the anti-backflow drive signal is ensured, and the damage to the circuit by the backflow current is effectively prevented.
[0081] In one embodiment of the present application, the anti-backflow module 50 also includes a voltage-stabilizing diode Q6; the first end of the voltage-stabilizing diode Q6 is respectively connected to the first end of the twelfth resistor R12, the input end of the first voltage conversion unit 121, the first end of the fifth capacitor C5, and the second end of the fourth switch tube Q5, and the second end of the voltage-stabilizing diode Q6 is respectively connected to the first end of the eleventh resistor R11, the second end of the twelfth resistor R12, the first end of the fourth capacitor C4, the second end of the fifth capacitor C5, and the controlled end of the fourth switch tube Q5.
[0082] In the technical solution provided by this embodiment, by providing the voltage stabilizing diode Q6, the reliable conduction of the fourth switch tube Q5 is ensured, the accurate transmission of the anti-backflow driving signal is ensured, and the damage to the circuit by the backflow current is effectively prevented.
[0083] In one embodiment of the present application, Figure 6 and Figure 7As shown, the input power supply 30 is a 24V input voltage, the filtering module 50 is the sixth capacitor C6, the first voltage conversion unit 121 and the second voltage conversion unit 122 are BUCK chips, the processor unit 11 is an MCU, the controllable voltage stabilizing unit Q1 is a TL431, the first switch tube Q2 and the fourth switch tube Q5 are PMOS tubes, and the second switch tube Q3 and the third switch tube are NPN transistors.
[0084] When the system is powered on, the input voltage 24V_IN will gradually increase. When the output voltage 24V_OUT after filtering by the sixth capacitor C6 is not enough to turn on the controllable voltage stabilizing unit Q1, the controllable voltage stabilizing unit Q1, the first switch tube Q2 and the second switch tube Q3 are all turned off, the anti-backflow drive signal PWR-EN is a low-level signal, the third switch tube Q4 and the fourth switch tube Q5 are also turned off, and the current of the input voltage 24V_IN flows into the body diode of the fourth switch tube Q5; then as the input voltage 24V-IN gradually increases, when ... turned off, the controllable voltage stabilizing unit Q1, the first switch tube Q2 and the second switch tube Q3 are all turned off, the anti-backflow drive signal PWR-EN is a low-level signal, the third switch tube Q4 and the fourth switch tube Q5 are also turned off, and the current of the input voltage 24V_IN flows into the body diode of the fourth switch tube Q5; then as the input voltage 24V-IN gradually increases, when the output voltage 24V_OUT after filtering by the sixth capacitor C6 is turned off, the controllable voltage stabilizing unit Q1, the first switch tube Q2 and the second switch tube Q3 are all turned off, the anti-backflow drive signal PWR-EN is a low-level signal, the third switch When the output voltage 24V_OUT after the wave increases to a level that can turn on the controllable voltage stabilizing unit Q1, the controllable voltage stabilizing unit Q1 is turned on, and the first switch tube Q2 and the second switch tube Q3 are also turned on. On the one hand, the anti-backflow drive signal PWR-EN is a high-level signal, the third switch tube Q4 is turned on, and the fourth switch tube Q5 is turned on subsequently. The input voltage 24V_IN flows in through the DS terminal of the fourth switch tube Q5, and then the two subsequent bucks are turned on, and the MCU works normally; on the other hand, the power-off detection signal PWR-DET is a low-level signal, and the MCU does not perform the power-off retention operation.
[0085] When a power outage occurs due to a drop or interruption of the input power supply 30 or a system power-off shutdown, the input voltage 24V_IN gradually decreases. When the input voltage 24V_IN decreases to a voltage corresponding to the power-off condition, the controllable voltage stabilizing unit Q1 is turned off, and the first switch tube Q2 and the second switch tube Q3 are also turned off. At this time, on the one hand, the anti-backflow drive signal PWR-EN is a low-level signal, the third switch tube Q4 is turned off, and the fourth switch tube Q5 is turned off accordingly; on the other hand, the power-off detection signal PWR-DET is pulled to a high-level signal, and the MCU performs a power-off retention operation under the power supply of the energy storage voltage VDD-MCU. As the energy storage voltage VDD-MCU is exhausted, the power-off detection signal PWR-DET eventually becomes a low-level signal. The time from the moment the power-off detection signal PWR-DET converts to a high level to the moment it finally becomes a low level is the time it takes for the system to perform the power-off retention operation.
[0086] In this embodiment, when the entire system is working normally, the voltage V acting on the controllable voltage stabilizing unit Q1 is REF As shown in formula (1):
[0087]
[0088] When V REF When the voltage is greater than 2.5V, the controllable voltage stabilizing unit Q1 is turned on. After the voltage is turned on, the controllable voltage stabilizing unit Q1 has a cathode voltage V KA , the GS terminal voltage of the first switch tube Q2 is V GS2 As shown in formula (2):
[0089]
[0090] Set the resistance of R3 and R4 so that V GS2 The value is greater than the turn-on voltage threshold V of the first switch tube Q2 GS2(th) When the first switch tube Q2 is turned on, the voltage V PWR_EN As shown in formula (3):
[0091]
[0092] Among them, R DS2(on) is the on-state internal resistance of the first switch tube Q2. DS2(on) Compared to R5, it is very small, so V PWR_EN Approximately equal to 5V_IN, V PWR_EN Acting on R6 and R7, the second switch tube Q3 is turned on. At this time, the voltage at the power-down detection signal PWR_DET end is equal to the voltage drop V when the second switch tube Q3 is saturated and turned on. CE3 .
[0093] When the input power 30 drops, is interrupted, or the system is powered off and a power outage occurs, the output voltage 24V-OUT gradually decreases. REF When the voltage is less than 2.5V, the controllable voltage stabilizing unit Q1 is turned off. At this time, the voltage V acting on the GS terminal of the first switch tube Q2 is GS2 When the voltage is close to 0V, the first switch tube Q2 is turned off, the anti-backflow driving signal PWR_EN is a low-level signal, the second switch tube Q3 is also turned off, and the voltage at the power-down detection signal PWR_DET end is equal to the energy storage voltage VDD_MCU. This power-down detection signal PWR_DET is transmitted to the MCU to notify it to perform the power-down retention operation.
[0094] Further, in combination with the anti-backflow module 40, an analysis is performed. When the system is powered on, the input voltage 24V_IN gradually increases. When the output voltage 24V_OUT after filtering by the sixth capacitor C6 is not enough to turn on the controllable voltage stabilizing unit Q1, the controllable voltage stabilizing unit Q1, the first switch tube Q2, and the second switch tube Q3 are all turned off. The anti-backflow driving signal PWR-EN is a low-level signal. The third switch tube Q4 and the fourth switch tube Q5 are also turned off. The input voltage 24V_IN flows into the system through the body diode of the fourth switch tube Q5. At this time, the system load capacity is very weak, and there is a voltage drop V across the fourth switch tube Q5. SD5 , 24V_OUT voltage is equal to 24V_IN minus V SD5 , the voltage V acting on the controllable voltage stabilizing unit Q1 REF As shown in formula (4):
[0095]
[0096] From formula (4), it can be seen that the voltage detection threshold V of the power failure detection signal PWR_DET before the fourth switch tube Q5 is turned on is DET1 As shown in formula (5):
[0097]
[0098] If V REF When the voltage is greater than 2.5V, as shown in formula (2) and formula (3), the controllable voltage stabilizing unit Q1 is turned on, the first switch tube Q2 is turned on, the anti-backflow driving signal PER_EN is a high-level signal, and the voltage V acting on the third switch tube Q4 is BE4 As shown in formula (6):
[0099]
[0100] When V BE4 When the voltage is greater than the conduction threshold, the third switch tube Q4 is turned on. At this time, the collector voltage of the third switch tube Q4 is equal to the saturation conduction voltage drop V of the third switch tube Q4. CE4 , the voltage V acting on the GS terminal of the fourth switch tube Q5 GS5 As shown in formula (7):
[0101]
[0102] When V GS5 The voltage is greater than the conduction threshold V of the fourth switch tube Q5 GS5(th) When the fourth switch tube Q5 is turned on, the current flows through the DS terminal of the fourth switch tube Q5, and the load capacity of the system is enhanced. After the fourth switch tube Q5 is turned on, the voltage drop V DS5 Equal to the current I OUT Multiply by R DS5(on), R DS5(on) is the on-state internal resistance of the first switch tube Q2, and equation (4) can be rewritten as equation (8):
[0103]
[0104] 24V-OUT forms the voltage required by the system through the two subsequent BUCKs, while 5V_IN and VDD_MCU provide voltage for the power-off detection module 20 to operate.
[0105] The V of the controllable voltage stabilizing unit Q1 REF The accuracy range affected by temperature is usually within 2%. The threshold voltage V of the power-down detection signal PWR-DET can be obtained from formula (8): DET2 With V REF The relationship is shown in formula (9):
[0106]
[0107] Where V REF The voltage is affected by temperature within 2% of the original value. DS5(on) It is a characteristic parameter of MOS tube, which will change with temperature. However, the internal resistance of mΩ level is much lower than that of V REF Very small, at the same time, by adjusting the parameters of R1 and R2, V DET2 The accuracy is maintained within 2% within a certain temperature range. SD5 The voltage drop is greater than the voltage drop when conducting V DS5 , so the voltage V when the fourth switch tube Q5 is not turned on DET1 Greater than the on-state voltage V DET2 .
[0108] In the technical solution provided in this embodiment, a circuit structure comprising a TL431, a PMOS transistor, and a transistor is used to transmit the power-failure detection signal PWR-DET. Due to the TL431's inherent temperature characteristics, its voltage is minimally affected by temperature. This ensures accurate transmission of the power-failure detection signal over a wide temperature range, improving the accuracy of power-failure detection.
[0109] The present application also provides an electronic device, which includes the power-off detection circuit 100 in any of the above embodiments. The specific structure of the power-off detection circuit 100 refers to the above embodiments. Since the electronic device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.
[0110] The corresponding technical features in the above-mentioned embodiments can be used interchangeably without causing contradiction or impracticality of the solutions.
[0111] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.
[0112] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.
[0113] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present application.
[0114] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are protected by this application.
Claims
1. A power-off detection circuit, characterized in that: The power-off detection circuit comprises: a control module, wherein an input terminal of the control module is connected to an input power supply, and the control module includes a processor unit; a power-off detection module, the power-off detection module comprising a controllable voltage stabilizing unit, a first switching tube, and a second switching tube, wherein a controlled end of the controllable voltage stabilizing unit is connected to the input power supply, a second end of the controllable voltage stabilizing unit is connected to the controlled end of the first switching tube, a first end of the controllable voltage stabilizing unit is grounded, a second end of the first switching tube is connected to a first output end of the control module, a first end of the first switching tube is respectively connected to the controlled end of the second switching tube and ground, a second end of the second switching tube is respectively connected to the second output end of the control module and the controlled end of the processor unit, and a first end of the second switching tube is grounded; The power-off detection module is configured to output a power-off detection signal when the output voltage of the input power source meets a power-off condition, so that the processor unit of the control module performs a power-off holding operation based on the power-off detection signal.
2. The power-off detection circuit according to claim 1, wherein: The power-off detection circuit further includes an anti-backflow module, wherein an input end of the anti-backflow module is connected to the input power supply, an output end of the anti-backflow module is respectively connected to an input end of the control module and a controlled end of the controllable voltage stabilizing unit, and a controlled end of the anti-backflow module is respectively connected to a first end of the first switching tube and a controlled end of the second switching tube; The anti-backflow module is configured to perform an anti-backflow protection operation based on the anti-backflow driving signal output by the power-off detection module when the output voltage of the input power source meets a power-off condition.
3. The power-off detection circuit according to claim 2, wherein: The anti-backflow module includes a third switch tube and a fourth switch tube; The controlled end of the third switch tube is respectively connected to the first end of the first switch tube and the controlled end of the second switch tube, the first end of the third switch tube is respectively connected to the controlled end of the fourth switch tube and the input end of the control module, the second end of the third switch tube is grounded, the first end of the fourth switch tube is connected to the input power supply, and the second end of the fourth switch tube is connected to the input end of the control module.
4. The power-off detection circuit according to claim 3, wherein: The control module further includes a voltage conversion unit; The input end of the voltage conversion unit is connected to the second end of the fourth switch tube, the first output end of the voltage conversion unit is connected to the second end of the first switch tube, and the second output end of the voltage conversion unit is respectively connected to the input end of the processor unit and the second end of the second switch tube.
5. The power-off detection circuit according to claim 4, wherein: The voltage conversion unit includes a first voltage conversion unit and a second voltage conversion unit; The input end of the first voltage conversion unit is connected to the second end of the fourth switch tube, the output end of the first voltage conversion unit is respectively connected to the input end of the second voltage conversion unit and the second end of the first switch tube, and the output end of the second voltage conversion unit is respectively connected to the input end of the processor unit and the second end of the second switch tube.
6. The power-off detection circuit according to claim 5, wherein: The power-off detection circuit further includes a filter module, wherein a first end of the filter module is respectively connected to the second end of the fourth switch tube and the input end of the first voltage conversion unit, and a second end of the filter module is respectively connected to the second end of the third switch tube and ground; The filtering module is used to filter the voltage output by the backflow prevention module.
7. The power-off detection circuit according to claim 6, wherein: The power failure detection module further includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, and a second capacitor; The second end of the first resistor is connected to the second end of the fourth switching transistor, the first end of the filtering module, and the input end of the first voltage conversion unit. The first end of the first resistor is respectively connected to the controlled end of the controllable voltage stabilizing unit and the second end of the second resistor. The first end of the second resistor is respectively connected to the first end of the controllable voltage stabilizing unit and the ground. The first end of the third resistor is connected to the second end of the controllable voltage stabilizing unit. The second end of the third resistor is respectively connected to the controlled end of the first switching transistor and the first end of the fourth resistor. The second end of the fourth resistor is respectively connected to the output end of the first voltage conversion unit and the second end of the first switching transistor. The second end of the fifth resistor is respectively connected to the first end of the first switching transistor, the controlled end of the third switching transistor, and the first end of the sixth resistor. The first end of the fifth resistor is grounded. The second end of the sixth resistor is respectively connected to the controlled end of the second switching transistor and the second end of the seventh resistor. The first end of the seventh resistor is respectively connected to the first end of the second switching transistor and the ground. The second end of the eighth resistor is connected to the output end of the second voltage conversion unit. The first end of the eighth resistor is respectively connected to the second end of the second switching transistor and the controlled end of the processor unit. The second end of the first capacitor is respectively connected to the first end of the first resistor, the second end of the second resistor and the controlled end of the controllable voltage stabilizing unit, the first end of the first capacitor is respectively connected to the first end of the second resistor, the first end of the controllable voltage stabilizing unit and the ground, the second end of the second capacitor is respectively connected to the second end of the sixth resistor, the second end of the seventh resistor and the controlled end of the second switch tube, and the first end of the second capacitor is respectively connected to the first end of the seventh resistor, the first end of the second switch tube and the ground.
8. The power-off detection circuit according to claim 7, wherein: The anti-backflow module further includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a third capacitor, a fourth capacitor, and a fifth capacitor; The first end of the ninth resistor is respectively connected to the first end of the first switching transistor, the second end of the fifth resistor, and the first end of the sixth resistor; the second end of the ninth resistor is respectively connected to the controlled end of the third switching transistor and the first end of the tenth resistor; the second end of the tenth resistor is respectively connected to the second end of the third switching transistor and ground; the first end of the eleventh resistor is respectively connected to the controlled end of the fourth switching transistor and the second end of the twelfth resistor; the second end of the eleventh resistor is connected to the first end of the third switching transistor; and the first end of the twelfth resistor is respectively connected to the input end of the first voltage conversion unit and the second end of the fourth switching transistor; The first end of the third capacitor is respectively connected to the second end of the ninth resistor, the first end of the tenth resistor, the controlled end of the third switch tube and the second end of the fourth capacitor; the second end of the third capacitor is respectively connected to the second end of the tenth resistor, the second end of the third switch tube and the ground; the first end of the fourth capacitor is respectively connected to the first end of the eleventh resistor, the second end of the twelfth resistor, the controlled end of the fourth switch tube and the second end of the fifth capacitor; the first end of the fifth capacitor is respectively connected to the second end of the fourth switch tube, the first end of the twelfth resistor and the input end of the first voltage conversion unit.
9. The power-off detection circuit according to claim 8, wherein: The anti-backflow module also includes a voltage stabilizing diode; The first end of the voltage-stabilizing diode is respectively connected to the first end of the twelfth resistor, the input end of the first voltage conversion unit, the first end of the fifth capacitor, and the second end of the fourth switch tube, and the second end of the voltage-stabilizing diode is respectively connected to the first end of the eleventh resistor, the second end of the twelfth resistor, the first end of the fourth capacitor, the second end of the fifth capacitor, and the controlled end of the fourth switch tube.
10. An electronic device, characterized in that: The electronic device comprises the power-off detection circuit according to any one of claims 1 to 9.