Vehicle-mounted platform super capacitor discharge control circuit and implementation method

Abstract

The invention relates to a vehicle-mounted station super capacitor discharge control circuit and an implementation method, and the vehicle-mounted station super capacitor discharge control circuit comprises a super capacitor charging protection circuit module and a super capacitor discharge control circuit module which are connected through a VBAT network. The charging protection module is composed of an MOS tube protection module, a voltage reduction module, a current limiting module and a super capacitor module, the MOS tube protection module prevents efficiency reduction and heating, the voltage reduction module converts 15V voltage into 13V voltage for charging, and the current limiting module controls charging current. The discharging control module is composed of a filtering module, a control chip module and a diode protection module, the filtering module restrains ripples, the control chip module achieves discharging through a power switch, and the diode protection module prevents recharging current. By limiting the current during charging, the super capacitor is safer and more stable during charging, meanwhile, the super capacitor discharging control is added, the variable requirements are better met, the circuit design is simple, and the cost is low.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electronic technology of rail transit, and particularly relates to a super capacitor discharge control circuit for vehicle-mounted station and an implementation method thereof. BACKGROUND

[0002] With the continuous development of energy technology and energy storage devices, super capacitors have been widely used in electric vehicles, rail transit, power control and emergency power supply fields due to their high power density, long service life and fast charging and discharging characteristics. In the vehicle-mounted system of rail transit, super capacitors are often used as backup power sources to maintain the short-time operation of vehicle-mounted stations or control units when the main power supply is abnormally powered off, so as to ensure the safety of system data and uninterrupted communication.

[0003] However, the super capacitor discharge control circuit for vehicle-mounted stations in the prior art is mostly composed of discrete devices, such as a triode or a MOS tube directly controlling discharge. Although such a scheme has a simple structure, it has obvious deficiencies: first, the discharge control part has low integration, and an external driving circuit is needed to realize effective conduction control, resulting in a complex overall circuit and large size; second, the traditional circuit only has switching control function and lacks protection mechanisms such as overcurrent, overheat and electrostatic discharge (ESD), which are easily disturbed and lead to failure in the complex electromagnetic environment of rail transit; third, in order to realize basic protection function, additional detection and protection modules need to be added, which not only increases the design cost but also increases the maintenance difficulty; fourth, in the charging link, if the input voltage and the output voltage are close, the existing scheme is prone to problems such as serious heating of power devices and low efficiency, which affects the system stability and service life.

[0004] Therefore, there is an urgent need for a super capacitor discharge control circuit for vehicle-mounted stations with simplified circuit structure, perfect protection function, high charging and discharging efficiency and low cost, to solve the above problems and meet the demand of rail transit equipment for high reliability emergency power supply. SUMMARY

[0005] The present application aims to solve the problem of lack of stable emergency power support for existing vehicle-mounted equipment in the case of power failure, and provides a super capacitor discharge control circuit for vehicle-mounted station with compact structure, low cost and high reliability, to solve the problems of complex circuit design, lack of protection function and low energy utilization efficiency in the prior art.

[0006] To achieve the above object, the application adopts the following technical scheme: a vehicle-mounted station super capacitor discharging control circuit, comprising: a super capacitor charging protection circuit module and a super capacitor discharging control circuit module; the super capacitor charging protection circuit module comprises a MOS tube protection module, a step-down module, a current limiting module and a super capacitor module, the MOS tube protection module is used for providing a low voltage drop protection path between an input end and the super capacitor module to prevent efficiency reduction and heat increase when the input and output voltages are close; the step-down module is used for converting an external input voltage into a constant output voltage to charge the super capacitor module; the current limiting module is used for controlling the charging current to prevent overcurrent; the super capacitor discharging control circuit module comprises a filtering module, a control chip module and a diode protection module, the filtering module is used for smoothing the discharging output signal, the control chip module is used for driving a power switch to realize discharging control according to a control signal, and the diode protection module is used for preventing load back-feeding current; the super capacitor charging protection circuit module and the super capacitor discharging control circuit module are connected through a VBAT network to realize short-time emergency power supply of the vehicle-mounted device in the power-off state of the external power supply.

[0007] Further, the implementation method of the vehicle-mounted station super capacitor discharging control circuit comprises the following steps: Step 1: external power supply input and system start; an external power supply device inputs a 15V direct current voltage to the circuit through a power input socket, the voltage is input to the super capacitor charging protection circuit module, an input protection circuit is formed through a self-resetting fuse and a reverse connection protection diode to realize overcurrent and polarity protection; Step 2: DC-DC step-down voltage stabilization and constant current charging; the DC-DC power supply chip in the charging protection module starts to work, a step-down voltage stabilization loop is formed through an external inductor, a diode and a feedback resistance network to stably step down the input voltage to 13V output, and the super capacitor module is charged with constant voltage and current limiting; Step 3: super capacitor energy storage establishment; under the constant voltage output, the super capacitor module absorbs energy and stores electric charge, the current limiting and feedback network jointly regulate the charging current to prevent inrush and ensure safe charging of the capacitor and entering the discharging standby state; Step 4: discharging control module conduction; when the external main power supply is disconnected or the voltage is detected to drop, the super capacitor discharging control circuit module automatically takes over the power supply; the load switch control chip is turned on when receiving a high level control signal to make the super capacitor discharge to the output end through the VBAT network; Step 5: emergency power supply maintenance; the super capacitor releases the stored energy to provide a stable voltage output to the load through the load switch control chip; the diode in the discharging path realizes one-way conduction and prevents back-feeding current to ensure safe and stable discharging process; Step 6: the end of discharging and system reset; when the super capacitor voltage drops to the set threshold, the control signal returns to the low level, the load switch control chip is turned off, and the discharging path is disconnected; the control circuit quickly releases the residual charge, so that the system returns to the initial standby state and is ready for the next cycle.

[0008] Compared with the prior art, the present application has the following beneficial effects: Firstly, the existing vehicle-mounted station super capacitor discharging circuit mostly adopts a direct driving mode of a triode or a MOS tube, and needs to be externally connected with a complex driving and protection circuit, so that the structure is dispersed and the integration degree is low. The present application realizes the integrated design of the discharging control and the multiple protection functions by adopting the high-integration-degree FDC6330L load switch control chip, significantly simplifies the circuit structure, reduces the number of peripheral elements, and improves the system reliability and integration degree.

[0009] Secondly, the existing circuit often has problems such as excessive inrush current, reduced efficiency and serious device heating during the super capacitor charging stage. The present application introduces a MOS tube protection loop and a step-down current limiting circuit in the charging protection module, effectively suppresses the inrush current at the initial charging stage, maintains the constant voltage and current limiting state, thereby improving the charging efficiency and prolonging the service life of the super capacitor.

[0010] Thirdly, in view of the characteristics that the running environment of the vehicle-mounted station of the rail transit is complex, and the power supply is easily affected by static electricity interference and power supply fluctuation, the present application designs multiple protection measures in the circuit, including self-recovery fuse overcurrent protection, reverse connection protection, overheat and ESD protection mechanisms, which can effectively prevent abnormal current and external interference from damaging the system, and ensure the safety and stability of the discharging process.

[0011] Finally, the existing solutions generally have problems such as large size, high cost and complex maintenance. The present application greatly reduces the PCB occupation area and material cost through high-integration-degree chips and modular design, simplifies the assembly process, and is suitable for mass production and long-term stable application in the vehicle-mounted environment.

[0012] In summary, the present application realizes the vehicle-mounted emergency power supply circuit solution with high integration degree, high efficiency, strong safety and low cost through the system optimization of the super capacitor charging and discharging control mode, effectively solves the problems of complex structure, insufficient protection and poor reliability existing in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The figure is a connection relationship block diagram among the modules of the present application. Figure 2 The figure is a super capacitor charging protection circuit module circuit diagram of the present application. Figure 3 The figure is a super capacitor discharging control circuit module circuit diagram of the present application. Figure 4The environment for building an embodiment of the present application and a test result schematic diagram. DETAILED DESCRIPTION

[0014] The technical solutions of the present application are further illustrated below in combination with the drawings and the specific embodiments.

[0015] As Figure 1 shown, the present application relates to a vehicle-mounted station super capacitor discharge control circuit, which comprises two parts of a super capacitor charging protection circuit module and a super capacitor discharge control circuit module. The super capacitor charging protection circuit module is composed of a MOS tube protection module, a step-down module, a current limiting module and a super capacitor module; the MOS tube protection module is used to provide a low voltage drop protection path between the input power supply and the super capacitor module, to prevent efficiency reduction and device heat increase caused by the input and output voltages being close to each other; the step-down module is used to convert the external input voltage (15V) into a stable voltage suitable for super capacitor charging; the current limiting module is used to limit the charging current to avoid the generation of inrush current of the super capacitor in the initial charging stage. The modules work together to realize safe and efficient charging of the super capacitor. The super capacitor discharge control circuit module is composed of a filter module, a control chip module and a diode protection module; the filter module is used to suppress power supply ripple and stabilize the discharge output voltage; the control chip module is used to receive control signals and drive power switches to realize discharge control; and the diode protection module is used to prevent damage to the circuit caused by load back-feeding current. The above-mentioned functional modules can be realized by independent circuit units, or can be realized in an integrated manner according to design requirements. The two modules are connected through a VBAT network; when the vehicle-mounted power supply input is normal, the charging protection module performs constant voltage and current limiting charging on the super capacitor; when the external power supply is disconnected, the discharge control circuit module drives the super capacitor to discharge through the control chip module, to provide short-time emergency power supply for the load device, thereby realizing continuous power supply protection under abnormal power supply conditions. The control signal CON_CAP in the discharge control circuit can be output by the power management logic of the vehicle-mounted station control unit, or can be automatically generated by the voltage detection circuit, to realize automatic or externally triggered discharge control.

[0016] As Figure 2 shown, in the super capacitor charging protection circuit module of the present application, the specific circuit connection relationship is as follows: The 6th pin of the DC-DC power chip N2 is connected to the resistor R5, one end of the capacitor C4 and the capacitor C2, and the negative electrode of the diode VD2; the positive electrode of the diode VD2 is connected to the negative electrode of the diode VD1 via the 15V network, and is connected to one end of the self-resetting fuse F1; the other end of the self-resetting fuse F1 is connected to the 1st pin of the power input socket XS1; the other end of the capacitor C4 and the capacitor C2, the positive electrode of the diode VD1 and the 2nd pin of the power input socket XS1 are grounded together. The 7th pin and the 8th pin of the DC-DC power chip N2 are connected to the other end of the resistor R5, and are connected to the 1st pin of N2, the 2nd pin of the triode VT1 and the 5th pin, the 6th pin, the 7th pin, the 8th pin and the 9th pin of the field effect tube VT2. The 2nd pin of the DC-DC power chip N2 is connected to the 4th pin of the field effect tube VT2, one end of the resistor R6 and the 3rd pin of the triode VT1; the 1st pin of the triode VT1 is connected to the negative electrode of the diode VD4, the 1st pin, the 2nd pin and the 3rd pin of the field effect tube VT2, and one end of the inductor L1. The 3rd pin of the DC-DC power chip N2 is connected to one end of the capacitor C6; the 4th pin of N2, the other end of the capacitor C6, the other end of the resistor R6 and the positive electrode of the diode VD4 are grounded together. The other end of the inductor L1 is connected to the capacitor C7, the capacitor C8, the capacitor C9, one end of the resistor R7 and the positive electrode of the diode VD5; the negative electrode of the diode VD5 is connected to the 1st pin of the super capacitor module XS3 via the VBAT network; the other end of the capacitor C7, the capacitor C8 and the capacitor C9 and the 2nd pin of the super capacitor module XS3 are grounded together. The 5th pin of the DC-DC power chip N2 is connected to the other end of the resistor R7 and one end of the resistor R8 via the FB network, and the other end of the resistor R8 is grounded.

[0017] In the present application, the model of the DC-DC power chip N2 in the super capacitor charging protection circuit module is MC33063A, the models of the diode VD2, the diode VD4 and the diode VD5 are DST560S, the model of the diode VD1 is SK34A-LTP, the model of the self-resetting fuse F1 is SMDC310F / 18, the model of the field effect tube VT2 is AON6552, the model of the triode VT1 is MJE180G, the model of the inductor L1 is PRS8040-221MT, and the model of the super capacitor module XS3 is MK-16V-P10FYS.

[0018] In the application, the core function of the super capacitor charging protection circuit module is to stabilize and step down the 15V voltage inputted from outside and control the charging current through the DC-DC power supply chip N2. The chip contains oscillator, error amplifier, switching transistor and other modules inside, can form a voltage feedback loop through the feedback end FB and the external resistance R7, R8, and realize stable output of 13V voltage. At the same time, the inductor L1 and the diode VD5 form an energy storage-release circuit, when the chip N2 internal switch is turned on, the inductor stores energy, and when it is turned off, the inductor releases energy, so that the energy is smoothly transferred to the super capacitor module, realizing continuous constant voltage charging. In addition, the design of current limiting resistor and sampling network ensures that the super capacitor charging current will not exceed the safety threshold, thereby preventing overheating and shortening the service life; the self-resetting fuse F1 is used for input overcurrent protection, which automatically limits the current when the input current is too large and restores after the fault is eliminated; the diode VD1 realizes reverse connection protection to prevent input power polarity error; VD2 and VD4 are used as rectifier and freewheeling diodes respectively to ensure continuous energy transfer during switching of the power supply chip N2. The MOS tube VT2 expands the load capacity of the chip N2 as an external power tube, and its low voltage drop characteristic can significantly improve the conversion efficiency and reduce the heat loss when the input and output voltage difference is small; the triode VT1 is used to provide a reference drive, so that VT2 can be reliably turned on or turned off, preventing false action caused by voltage drift. The inductor L1 and the capacitors C7-C9 together form an LC filter network to suppress output ripple and ensure stable charging voltage.

[0019] As shown in Figure 3 The specific circuit connection relationship in the super capacitor discharging control circuit module of the application is as follows: The 6th pin of the load switch control chip N1 is connected with one end of the resistor R1 and one end of the capacitor C3; the 4th pin of the load switch control chip N1 is connected with the other end of the resistor R1, one end of the capacitor C1 and the VBAT network; the other end of the capacitor C1 is grounded. The 2nd pin and the 3rd pin of the load switch control chip N1 are connected with the other end of the capacitor C3, one end of the capacitor C5 and the positive electrode of the diode VD3; the other end of the capacitor C5 is grounded; the negative electrode of the diode VD3 is connected to the 1st pin of the power output socket XS2 through the VOUT network. The 1st pin of the load switch control chip N1 is connected with one end of the resistor R4, and the other end of the resistor R4 is grounded. The 5th pin of the load switch control chip N1 is connected with one end of the resistor R2, the other end of the resistor R2 is connected with one end of the resistor R3, and the other end of the resistor R3 is connected to the 2nd pin of the power output socket XS2 through the CON_CAP network; the other end of the resistor R3 is grounded; the 3rd pin, the 4th pin and the 5th pin of the power output socket XS2 are all grounded.

[0020] The model of the load switch control chip N1 in the super capacitor discharging control circuit module is FDC6330L, and the model of the diode VD3 is DST560S.

[0021] The supercapacitor discharge control circuit module of this invention is based on the load switch control chip N1. This chip integrates a P-channel MOS power switch, a drive circuit, and multiple protection circuits (including overcurrent, overheat, and ESD protection). It is connected to the external control signal CON_CAP via its control pin ON / OFF. When a high level is applied to the control terminal, the MOS transistor conducts, and the supercapacitor discharges to the output terminal VOUT through VBAT, providing a stable 12V power supply to the load. When the control terminal is low, the MOS transistor is turned off, preventing reverse discharge of the supercapacitor. Diode VD3 provides a unidirectional conduction path during discharge, preventing backflow current from damaging the switch chip. R1 and C1 form a soft-start delay network to prevent inrush current from the supercapacitor's instantaneous discharge. R2 and R3 form a voltage divider circuit for current limiting and level adjustment of the control terminal signal. C3 and C5 act as filters and decouplers, ensuring the stability of the FDC6330L control terminal signal. Diode VD3 provides reverse protection in the discharge path, allowing energy to flow only from the supercapacitor to the load. The system can achieve rapid and reliable emergency power supply switching by controlling the high-level signal at the CON_CAP terminal.

[0022] Example 1: The test environment for implementing the present invention is as follows: Figure 4 As shown, the supercapacitor charging protection circuit module and the supercapacitor discharge control circuit module are connected to form a vehicle-mounted discharge control circuit of the present invention. An external DC power supply is used to power the present invention. The power input socket XS1 is connected to the present invention, and the power output socket XS2 is connected to the vehicle-mounted control unit. The environment is set up in this way.

[0023] The implementation method of the vehicle-mounted supercapacitor discharge control circuit of the present invention includes the following steps: Step 1: External power input - System power-on startup: An external power supply device (such as a vehicle power system) inputs a 15V DC voltage into the circuit. This voltage is connected to the supercapacitor charging protection circuit module through a power input socket. The input terminal is equipped with a self-resetting fuse and a reverse polarity protection diode, which automatically disconnects the circuit in case of power supply abnormalities (such as short circuits or reverse polarity) to prevent system damage. After passing through this module, the input voltage provides the energy basis for the voltage regulation and charging process of the entire circuit.

[0024] Step 2: DC-DC buck conversion - constant voltage current limiting charging: After the super capacitor charging protection circuit module is started, the DC-DC power supply chip starts to work. The chip internally integrates an oscillator, an error amplifier and a switching transistor, and forms a step-down voltage stabilizing circuit through an external inductor, a diode and a feedback resistor. The input 15V voltage is stably stepped down to 13V through a high-frequency switching mode, and a constant voltage output is provided for the super capacitor module charging; the inductor stores energy when the switch is turned on, and releases energy when the switch is turned off, providing smooth current to the VBAT network and realizing continuous charging; the current limiting resistor and the sampling feedback network ensure that the charging current does not exceed the safety threshold, preventing overheating and prolonging the service life of the super capacitor.

[0025] Step 3: Super capacitor charging phase-energy reserve establishment: Under the constant voltage output provided by the DC-DC module, the super capacitor module starts to charge. The charging voltage is about 13V, and the capacitor module absorbs energy and stores charge in a short time; the charging process is dynamically adjusted by the current limiting and feedback network to avoid the impact of inrush current on the power supply and capacitor; when the voltage reaches the predetermined value, the system remains in the floating state to ensure that the capacitor is always ready to discharge.

[0026] Step 4: Discharge control module starts-load switch control chip turns on: When the external main power supply is disconnected or the load detects a voltage drop, the super capacitor discharge control circuit module automatically takes over the power supply; the module takes the load switch control chip N1 as the core, which internally integrates a P-channel MOS power tube, a drive circuit and multiple protection functions such as overcurrent, overheating and ESD; when the control signal CON_CAP receives a high level from the external control system, the load switch control chip turns on, allowing the super capacitor to discharge through the VBAT network to the output terminal VOUT to provide a stable 12V power supply for the vehicle-mounted device; the diode in the discharge path ensures one-way conduction to prevent the chip from being damaged by backflow current.

[0027] Step 5: Emergency power supply phase-capacitor discharge maintains operation: In the discharge phase, the super capacitor releases stored energy to maintain the load for a short time; the output voltage is regulated by the load switch control chip to remain stable, with a ripple of less than 40mV, which can ensure that the vehicle-mounted station or rail transit control unit can still work for several seconds in a power-off state; the output stability in this phase depends on the internal feedback and current limiting characteristics of the load switch control chip, and the 200μA level of static current design greatly reduces energy loss and prolongs the discharge time of the super capacitor.

[0028] Step 6: Discharge ends and system resets: When the super capacitor voltage drops to the set threshold, the discharge control module is automatically turned off. The control terminal signal CON CAP returns to low level, the internal MOS of the load switch control chip is turned off, and the discharge path is cut off. Through the internal fast discharge path and the parallel resistance circuit, the control signal is released in time, the system returns to the initial standby state, and waits for the next power input. The whole process realizes automatic switching, smooth discharge and safety protection, ensuring the reliable short-time power supply capability of the vehicle-mounted equipment in abnormal power supply.

[0029] In the test environment, the DC power input is 15V, which is reduced to 13V by the DC-DC power chip and charges the super capacitor. The charging current is controlled by the current limiting resistor and feedback network to remain stable. After the external power is disconnected, FDC6330L is turned on under the action of the control signal, and the super capacitor discharges through VD3 to VOUT. Due to the built-in overcurrent limiting and thermal shutdown function of FDC6330L, the discharge process is safe and stable, and the voltage fluctuation is less than ±0.1V.

[0030] The test results and methods are as follows: first step: after the environment is built, adjust the DC power to 15V input and start the power supply, and keep the rest unchanged. Charge the super capacitor for at least 10 minutes; second step: measure the CON CAP network level with an oscilloscope. When it is 3.3V high level, move the oscilloscope probe to the VOUT network to measure the voltage; third step: turn off the DC power. The VOUT network level can be observed to be a stable output of 12V voltage by the oscilloscope. The waveform is stable, the ripple is maintained at about 40mV fluctuation, and the load vehicle-mounted control unit power indicator light can be observed to normally flicker and work normally.

Claims

1. A vehicle-mounted supercapacitor discharge control circuit, characterized in that: The super capacitor charging protection circuit module comprises a MOS tube protection module, a step-down module, a current limiting module and a super capacitor module, the MOS tube protection module is used for providing a low voltage drop protection path between an input end and the super capacitor module, the step-down module is used for converting an external input voltage into a constant output voltage to charge the super capacitor module, and the current limiting module is used for controlling a charging current to prevent overcurrent.

2. The on-board bench supercapacitor discharge control circuit of claim 1, wherein: The circuit connection relationship of the super capacitor charging protection circuit module is as follows: the sixth pin of the DC-DC power supply chip N2 is connected with the resistor R5, one end of the capacitor C4, one end of the capacitor C2 and the negative electrode of the diode VD2; the positive electrode of the diode VD2 is connected with the negative electrode of the diode VD1 and one end of the self-resetting fuse F1 through the 15V network, the other end of the self-resetting fuse F1 is connected with the first pin of the power input socket XS1; the other end of the capacitor C4, the other end of the capacitor C2, the positive electrode of the diode VD1 and the second pin of the power input socket XS1 are all connected with the ground; the seventh pin and the eighth pin of the DC-DC power supply chip N2 are connected with the other end of the resistor R5, the first pin of the DC-DC power supply chip N2, the second pin of the triode VT1 and the fifth to ninth pins of the field effect tube VT2; the second pin of the DC-DC power supply chip N2 is connected with the fourth pin of the field effect tube VT2, one end of the resistor R6 and the third pin of the triode VT1; the first pin of the triode VT1 is connected with the negative electrode of the diode VD4, the first to third pins of the field effect tube VT2 and one end of the inductor L1; the third pin of the DC-DC power supply chip N2 is connected with one end of the capacitor C6; the fourth pin of the DC-DC power supply chip N2, the other end of the capacitor C6, the other end of the resistor R6 and the positive electrode of the diode VD4 are connected with the ground; the other end of the inductor L1 is connected with the capacitor C7, the capacitor C8, the capacitor C9, one end of the resistor R7 and the positive electrode of the diode VD5; the negative electrode of the diode VD5 is connected with the first pin of the super capacitor module XS3 through the VBAT network; the other ends of the capacitor C7, the capacitor C8 and the capacitor C9 and the second pin of the super capacitor module XS3 are connected with the ground; the fifth pin of the DC-DC power supply chip N2 is connected with the other end of the resistor R7 and one end of the resistor R8 through the FB network, and the other end of the resistor R8 is connected with the ground.

3. The on-board bench supercapacitor discharge control circuit of claim 2, wherein: The DC-DC power chip N2 is model MC33063A; diodes VD2, VD4, and VD5 are all model DST560S; diode VD1 is model SK34A-LTP; resettable fuse F1 is model SMDC310F / 18; MOSFET VT2 is model AON6552; transistor VT1 is model MJE180G; inductor L1 is model PRS8040-221MT; and supercapacitor module XS3 is model MK-16V-P10FYS.

4. The on-board bench supercapacitor discharge control circuit of claim 1, wherein: The circuit connection relationship of the supercapacitor discharge control circuit module is as follows: Pin 6 of the load switch control chip N1 is connected to one end of resistor R1 and one end of capacitor C3; Pin 4 of the load switch control chip N1 is connected to the other end of resistor R1, one end of capacitor C1, and the VBAT network; the other end of capacitor C1 is grounded; Pins 2 and 3 of the load switch control chip N1 are connected to the other end of capacitor C3, one end of capacitor C5, and the positive terminal of diode VD3; the other end of capacitor C5 is grounded; the negative terminal of diode VD3 is connected to pin 1 of power output socket XS2 via the VOUT network; Pin 1 of the load switch control chip N1 is connected to one end of resistor R4, and the other end of resistor R4 is grounded; Pin 5 of the load switch control chip N1 is connected to one end of resistor R2, and the other end of resistor R2 is connected to one end of resistor R3 and then connected to pin 2 of power output socket XS2 via the CON_CAP network; the other end of resistor R3 is grounded; Pins 3, 4, and 5 of power output socket XS2 are grounded.

5. The on-board bench supercapacitor discharge control circuit of claim 4, wherein: The load switch control chip N1 is model FDC6330L; the diode VD3 is model DST560S.

6. The on-board bench supercapacitor discharge control circuit of claim 1, wherein: The method also includes a supercapacitor discharge control method based on the circuit, comprising the following steps: After external power is input, it enters the supercapacitor charging protection module through a self-resetting fuse and reverse connection protection circuit. The DC-DC step-down chip regulates and limits the input voltage, reducing the 15V input voltage to a constant 13V output voltage to charge the supercapacitor module. When the external main power is disconnected or the voltage drops, the discharge control module takes over the power supply and controls the supercapacitor to discharge to the output terminal through the VBAT network via the load switch control chip, providing a stable voltage output to the load. During the discharge process, the diode provides a unidirectional conduction path to prevent backflow current, and the control terminal signal realizes the discharge start / stop switching. When the supercapacitor voltage drops to a preset threshold, the discharge control module automatically closes the discharge path, restoring the system to standby state and completing one charge / discharge cycle.

7. The method of claim 1-6, wherein the method further comprises: The method includes the following steps: Step 1: External power input and system startup; The external power supply device inputs 15V DC voltage into the circuit. This voltage is connected to the supercapacitor charging protection circuit module through the power input socket. The input protection circuit is formed by the self-resetting fuse and the reverse connection protection diode to achieve overcurrent and polarity protection. Step 2: DC-DC step-down regulation and constant current charging; The DC-DC power chip in the charging protection module starts working, and forms a step-down regulation circuit through an external inductor, diode and feedback resistor network to stably step down the input voltage to 13V output, and perform constant voltage and current limiting charging on the supercapacitor module. Step 3: Supercapacitor energy storage setup; Under constant voltage output, the supercapacitor module absorbs energy and stores charge. Current limiting and feedback networks work together to regulate the charging current, prevent surges, ensure the capacitor is safely charged and enters the standby state. Step 4: The discharge control module is turned on; when the external main power supply is disconnected or a voltage drop is detected, the supercapacitor discharge control circuit module automatically takes over the power supply; when the load switch control chip receives a high-level control signal, it is turned on, allowing the supercapacitor to discharge to the output terminal through the VBAT network; Step 5: Emergency power supply maintenance; the supercapacitor releases its stored energy and provides a stable voltage output to the load via the load switch control chip; the diodes in the discharge path achieve unidirectional conduction and prevent backflow current, ensuring a safe and stable discharge process; Step 6: Discharge ends and system reset; When the supercapacitor voltage drops to the set threshold, the control signal returns to low level, the load switch control chip is turned off, and the discharge path is disconnected; The control circuit quickly releases the residual charge, allowing the system to return to the initial standby state and prepare to enter the next cycle.

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