1720 results about "Over current protection" patented technology

The invention is suitable for the technical field of LED backlight driving, and provides a starting control circuit for LED backlight driving, a chip and a display device. The starting control circuit of the LED backlight drive comprises a detection selection module, an error amplification module, a first change-over switch module, a control module, a second change-over switch module, a logic drive module, a feedback module and a first switch module. When each first voltage is in a preset range, the first change-over switch module is used for conducting the first input end of the error amplification module and the output end of the error amplification module. And the second change-over switch module is used for transmitting the overcurrent protection signal to the logic driving module. When the detection voltage is larger than the first reference voltage, the first change-over switch module is used for conducting the first input end of the error amplifier and the detection selection module. And the second change-over switch module is used for conducting the control module and the logic driving module. Therefore, the Boost has more response time to respond to the rapid change of the LED.

The invention discloses a power supply circuit, a power supply method, a server, a product and a medium, and relates to the technical field of server power supply, the total power demand of the server is dispersed through the parallel design of multiple power panels, the bus current of a single board connected to a first voltage is reduced to the safe bearing range of an MOS tube, the impact risk is reduced, and the service life of the server is prolonged. The electronic fuse is matched with the single-board power to set an overcurrent protection threshold value, and the short-circuit protection response time is shortened; each board is independently provided with a power supply brick to realize second voltage localization conversion and single board output current reduction, a multi-board output end combined power supply design is combined, a heat source is dispersed to eliminate heat accumulation, the through-current capability is multiplied through a parallel path, and the heat dissipation and electrical design feasibility of the circuit board is improved. The technical problems of MOS tube over-limit, overcurrent protection delay, circuit board heat accumulation and difficult through-flow caused by large current brought by a power supply in a high-power server are solved, and the technical effects of enhancing power supply reliability and optimizing energy efficiency are achieved.

According to the SiC MOSFET global short circuit and overcurrent protection circuit and the control method thereof provided by the invention, when a short circuit fault occurs in the SiC MOSFET, the drain current ID is more than several times of the rated current of the SiC MOSFET. When a short circuit occurs, a transistor QDZ of the short circuit detection circuit is switched on by node voltage Vr of the resistance-capacitance filter circuit, a fault signal VFAULT is converted into a low level, grid voltage VGS output by the grid control unit is gradually converted into zero voltage from negative driving voltage VEE, and soft turn-off is performed on the SiC MOSFET; when an over-current fault occurs in the SiC MOSFET, drain current ID is higher than rated current, node voltage Vo of the resistance-capacitance filter circuit lasts for a long time, the maximum value of capacitor voltage Vch of the over-current detection circuit is higher than reference voltage Vref2, a fault signal VFAULT is converted into low level, grid voltage VGS output by the grid control unit is gradually converted into zero voltage from negative driving voltage VEE, and soft turn-off is performed on the SiC MOSFET. According to the invention, high-speed short circuit and over-current fault protection of the SiC MOSFET in all inductance regions of a commutation loop can be realized.

The invention discloses a high-voltage power amplifier with an over-temperature and over-current protection circuit, and relates to the technical field of integrated circuits. The high-voltage operational amplifier comprises a high-voltage operational amplifier core unit and a self-adaptive protection circuit unit, the high-voltage operational amplifier core unit comprises a rail-to-rail input stage, a gain amplification stage and an AB type push-pull output stage which are sequentially cascaded, and the AB type push-pull output stage comprises a PMOS upper power tube and an NMOS lower power tube; the self-adaptive protection circuit unit comprises a PMOS (P-channel Metal Oxide Semiconductor) current-limiting protection circuit, an NMOS (N-channel Metal Oxide Semiconductor) current-limiting protection circuit and an over-temperature protection circuit; the PMOS current-limiting protection circuit is used for generating a high-voltage domain over-current control signal when the power tube on the PMOS is over-current; the NMOS current-limiting protection circuit is used for generating a low-voltage domain overcurrent control signal when the NMOS lower power tube is in overcurrent; the over-temperature protection circuit is used for generating high-voltage domain over-temperature turn-off signals and low-voltage domain over-temperature turn-off signals when the amplifier is over-temperature; and finally, carrying out logic synthesis on the corresponding over-current control signal and the over-temperature turn-off signal to generate a gate clamping signal.

The invention discloses a high-voltage LDO turn-back type overcurrent protection feed-forward circuit and an overcurrent protection method based on the high-voltage LDO turn-back type overcurrent protection feed-forward circuit. The high-voltage LDO turn-back type overcurrent protection feed-forward circuit comprises an LDO loop and an overcurrent protection loop. The LDO loop is used for generating an output voltage according to an input reference voltage of the first operational amplifier and providing a detection current and a feedback voltage; the over-current protection loop is used for introducing detection current, so that the positive end voltage of the second operational amplifier is increased, when it is detected that the positive end voltage is higher than feedback voltage, over-current protection is triggered to open the switch current mirror, and the switch current mirror controls the output end voltage of the first operational amplifier; and the current of the output end of the first operational amplifier is accurately copied to the output end of the LDO loop.

The utility model provides a wheel speed sensor signal analysis circuit, which is used for enabling the circuit to be compatible with a standard current type wheel speed sensor and an AK protocol current type wheel speed sensor at the same time, and comprises an overcurrent protection module, a current sampling resistor and a wheel speed signal output module, the overcurrent protection module is used for closing the connection with the wheel speed signal output module when the signal of the wheel speed sensor is short-circuited; the wheel speed signal output module is used for outputting a level signal corresponding to a wheel speed sensor signal; the overcurrent protection module is connected with one end of the current sampling resistor; one end of the current sampling resistor is connected with the wheel speed signal output module; the other end of the current sampling resistor is grounded.

The invention discloses a power supply intelligent protection control method and device and an intelligent power supply, and the method comprises the steps: carrying out the curve fitting of i historical voltages, and obtaining a historical voltage curve; performing curve fitting on the j historical currents to obtain a historical current curve; determining a first voltage curve of the intelligent power supply in a future time period according to the historical voltage curve; determining a first current curve of a future time period according to the historical current curve; determining an overvoltage protection threshold curve and an undervoltage protection threshold curve according to the load power curve of the future time period; determining an overcurrent protection threshold curve according to the load power curve; determining a target critical point according to the first voltage curve, the first current curve, the overvoltage protection threshold curve, the undervoltage protection threshold curve and the overcurrent protection threshold curve; and controlling the protection device to execute a power supply protection operation corresponding to the target critical point. The safety of the intelligent power supply can be improved.

The invention discloses an overcurrent protection control circuit of a low-dropout linear regulator and the low-dropout linear regulator, and relates to the field of voltage regulators. A first sampling module is connected with a drain electrode, a grid electrode and a source electrode of a power control tube in the low-dropout linear regulator and a first current comparator; the first current comparator is further connected with the grid electrode of the first protection switch and the input voltage end of the low dropout linear regulator, the source electrode of the first protection switch is connected with the grid electrode of the power control tube, the drain electrode of the first protection switch is grounded, and the source electrode of the power control tube is connected with the voltage output end of the low dropout linear regulator; the second sampling module is respectively connected with the drain electrode of the power control tube, the grid electrode of the power control tube and the clamping module, the clamping module is connected with the grid electrode of the second protection switch through the second current comparator and is also connected with the source electrode of the power control tube, the drain electrode of the second protection switch is grounded, and the source electrode of the second protection switch is connected with the grid electrode of the power control tube. The reliability of current limiting can be improved.

The invention discloses an overcurrent protection circuit and a BUCK type DC-DC converter, and relates to the technical field of integrated circuits. The over-current protection circuit can be applied to a BUCK type DC-DC converter, and comprises an over-current judgment circuit which is connected with the output end of the converter and is used for sampling a current signal output by the converter according to a preset proportion and converting the sampled current signal into an over-current detection signal; the digital logic module is connected with the output end of the overcurrent judgment circuit and the control end of the converter, and is used for sampling the overcurrent detection signal, counting overturning signals of the overcurrent detection signal in each switching period of the converter, judging whether the converter is in an overcurrent state or not on the basis of a count value, and if the converter is in the overcurrent state, outputting the overcurrent detection signal; and if so, outputting a turn-off signal to the converter to turn off the converter. The over-current protection circuit is simple in control logic and low in power consumption, and can prevent the occurrence of false touch in over-current detection.

The invention discloses a DTW algorithm-based distribution line current differential protection method, relates to the technical field of power distribution network relay protection, and aims to solve the problems that the III-section type overcurrent protection performance is reduced and the optical fiber communication cost is high after a distributed power supply is connected. According to the method, a 5G communication technology, a five-point numerical differential algorithm, amplitude limiting average filtering and a DTW similarity distance algorithm are fused, and current differential protection is achieved; the method comprises the steps of collecting three-phase current on two sides of a line in real time, starting a criterion through a fault current change rate, suppressing noise through amplitude-limiting average filtering, and normalizing data; the core is that the current sequence similarity is calculated by using a DTW algorithm, and a fault is accurately judged; according to the method, the influence of 5G communication time delay is eliminated, and the reliability of distribution network protection and control is improved; meanwhile, optical fibers are replaced by 5G, so that the cost is greatly reduced, the economical efficiency of distribution network protection is improved, and popularization and application are facilitated; the innovative technology provides powerful support for intelligent upgrading and sustainable development of a power distribution network.

The invention discloses a power supply processing circuit with slow start, combination and high-side eFuse functions, and the circuit comprises a slow start module which is used for the slow start of a power supply, and the slow start time is linearly adjustable; the high-side current-limiting e-Fuse module is used for simulating a single over-current fusing function of a common fuse through two self-reset switches to carry out over-current protection when the total current of the circuit reaches a threshold value, or simulating a self-recovery fuse through a self-locking switch to carry out over-current protection in a hiccup protection mode; the low-power-consumption combination module is used for realizing low-power-consumption multi-path power supply combination through discrete semiconductor devices; and the front protection module is used for providing bypass spike pulse voltage and a reverse connection prevention function for each power supply branch. According to the circuit, the circuit design is simplified, the cost is reduced, a stable and reliable power supply is provided, and meanwhile, the circuit can be integrated into a specific board card.

The invention discloses a frequency converter multi-stage cooperative rapid overcurrent protection circuit, and the overcurrent protection circuit cooperates with an IGBT inverter circuit, an IGBT drive circuit, a current sampling circuit and a master control MCU of a frequency converter to construct a three-stage cooperative protection system composed of hardware-stage extreme rapid protection, hardware-stage rapid protection and software-stage intelligent protection. And independent action and information interaction between the stages can be realized through circuit design. Compared with the prior art, protection blind areas are eliminated, nanosecond-microsecond level extreme protection is achieved, a multiple and high-reliability redundancy protection system is constructed, intelligent grading processing of faults is achieved, and the diagnosability of the system is enhanced.

The invention provides a turn-back overcurrent protection circuit and a linear voltage regulator, and the turn-back overcurrent protection circuit comprises a turn-back switch module which compares an output voltage with a preset voltage, and outputs a turn-back current when the output voltage is smaller than or equal to the preset voltage; and the overcurrent protection module is connected with the turn-back switch module, performs overcurrent protection on the linear voltage regulator based on the first current limiting point when the turn-back switch module does not output the turn-back current, and reduces the current limiting point from the first current limiting point to a second current limiting point based on the turn-back current when the turn-back switch module outputs the turn-back current, and over-current protection is carried out on the linear voltage regulator based on the second current limiting point. According to the invention, the problem of circuit damage caused by overlarge output current due to short circuit or overload in the prior art is solved.

The invention provides a silicon carbide MOS drive control chip overcurrent protection method and device, and the method comprises the steps: setting a forward sampling channel and a reverse sampling channel at a source sampling resistor, setting different sampling time windows for different sampling channels, carrying out the peak shifting setting of the time windows of the double sampling channels, and carrying out the peak shifting setting of the time windows of the double sampling channels, thereby achieving the overcurrent protection of a silicon carbide MOS drive control chip. The time period with the strongest common-mode interference can be avoided; meanwhile, the switching speed of the silicon carbide MOS device is mapped into a theoretical common-mode interference waveform, and the waveform and a bidirectional sampling signal are synthesized, so that a common-mode interference component in the sampling signal can be accurately separated, and the synthesized current signal is more accurate; on the basis, current signals are compensated by combining on-resistance change caused by junction temperature change, and overcurrent protection is carried out by adopting a graded protection strategy. According to the method, the influence of common-mode interference on current sampling is effectively overcome through peak shifting design on sampling channel time and common-mode interference separation based on switching speed.

A level conversion assembly (50), an overcurrent protection method and a display device, the level conversion assembly (50) comprising a level conversion module (51), the level conversion module (51) comprising a control unit (511), a current detection unit (512), a level conversion unit (513) and an overcurrent protection unit (514). When a control unit (511) is at a first falling edge of a digital clock signal (CPV), a first analog clock signal corresponding to the first falling edge in a plurality of analog clock signals (CLK1-CLK8) is determined based on the corresponding relation of the current display mode, and a current detection unit (512) is controlled to detect the current of the first analog clock signal. Since the moment of the falling edge of the digital clock signal (CPV) is located in the last row of the high level period or the low level period in the corresponding analog clock signal, the current detection unit (512) can send an overcurrent signal to the overcurrent protection unit (514) when the current of the first analog clock signal is not located in the current threshold range. The effect of improving the accuracy of over-current phenomenon detection is achieved.

The invention relates to an air conditioner anti-interference control method and device, an air conditioner and a storage medium, and the method comprises the steps that under the condition that the air conditioner is shut down, whether the shutdown reason is overcurrent protection or not is judged; under the condition that the shutdown reason is overcurrent protection, the filtering depth value of a protection pin of a main chip in the air conditioner is adjusted, and the air conditioner is restarted again after adjustment; and after the filtering depth value of the protection pin is adjusted to be maximum and the air conditioner is restarted, when the air conditioner is still shut down due to overcurrent protection, the capacitance value of the protection pin of a main chip in the air conditioner is adjusted. By means of the method and device, the problem that in the related technology, due to power grid voltage fluctuation, the air conditioner is correspondingly disturbed, and the air conditioner is mistakenly protected is solved.

The invention discloses an overcurrent protection method. The method comprises the following steps: acquiring overcurrent protection influence factors, wherein the overcurrent protection influence factors comprise temperature drift and voltage fluctuation; dynamic compensation is carried out on the basic overcurrent threshold value according to the overcurrent protection influence factors, and an overcurrent protection threshold value is obtained; the basic overcurrent threshold value is determined based on a wire harness impedance model; and under the condition that the real-time current value is greater than the overcurrent protection threshold value, triggering an overcurrent protection action so as to realize overcurrent protection of the protected object. Through dynamic compensation of the basic overcurrent threshold and integration of multi-dimensional influence factors such as temperature drift and voltage fluctuation, threshold deviation caused by the temperature drift and the voltage fluctuation is effectively eliminated, false triggering or protection failure is avoided, and the method has the advantages of improving overcurrent protection precision and system stability.

A DC electronic load circuit relates to the technical field of electronic load control. The utility model provides a direct current electronic load circuit which integrates a dissipation MOS tube array, an analog PID loop, a digital integrated control module, a bus electrical parameter sampling and processing module and a WiFi communication module, and realizes a plurality of working modes such as constant current, constant voltage, constant resistance and constant power by accurately controlling the conduction degree of the MOS tube array. The system has the advantages of real-time monitoring, remote control, overvoltage and overcurrent protection, low power consumption design and the like, and an electronic load solution which is high in precision, high in stability and flexible to operate is provided, so that diversified test requirements are met, and the power supply test efficiency and safety are improved.

The utility model relates to the technical field of batteries, and discloses a top cover assembly and a battery. The top cover assembly comprises a cover group assembly and a top cover assembly, the cover group assembly comprises a cover plate and a pole, the cover plate is connected with the opening of the shell, a first through hole is formed in the cover plate, one end of the pole is positioned on the inner side of the cover plate and is electrically connected with the tab of the battery cell, and the other end of the pole extends out of the outer side of the cover plate from the first through hole; the top cover assembly comprises a first connecting piece, a PTC and a top cover body which are sequentially connected in the direction away from the shell, and the first connecting piece is located above the cover plate and electrically connected with the pole. By adopting the arrangement mode, the top cover assembly can be connected with the opening of the shell by adopting a full-sealing structure, so that the battery has good sealing performance; by integrating the PTC, the over-current protection function in the assembling process of the top cover assembly can be achieved, and therefore the safety and reliability of the assembling process of the top cover assembly are guaranteed.

The invention discloses a converter valve multistage thyristor level closed-loop test device which comprises a CPU control module, a photoelectric conversion module, an analog quantity acquisition module, a switching value module, an output control unit, an impedance test unit, an overvoltage and overcurrent protection module, a safety protection module, a man-machine interaction unit module and a power supply module. The CPU control module is respectively connected with the photoelectric conversion module, the analog quantity acquisition module, the switching value module, the output control unit, the impedance test unit, the overvoltage and overcurrent protection module, the safety protection module and the man-machine interaction unit module; the power supply module is connected with the CPU control module, the safety protection module, the photoelectric conversion module, the analog quantity acquisition module, the overvoltage and overcurrent protection module, the switching value module, the output control unit, the impedance test unit and the man-machine interaction unit module. According to the invention, the automation degree and the field adaptability of the test are improved, and the field maintenance efficiency and the visual analysis capability of the operation state of the thyristor are improved.

The embodiment of the invention provides a gallium nitride totem-pole circuit and a control evaluation system of the gallium nitride totem-pole circuit, and the circuit comprises a gallium nitride power device which comprises an integrated semiconductor tube and an integrated drive circuit; the isolation chip is connected between the control module and an integrated driving circuit of the gallium nitride power device and is used for sending the pulse width modulation signal sent by the control module to the integrated driving circuit, and the isolation chip can ensure the electrical safety of weak current and strong current; the gallium nitride power device is used for controlling the on-off state of the integrated semiconductor tube through the integrated driving circuit according to the pulse width modulation signal sent by the isolation chip; under the condition that the integrated semiconductor tube is conducted, the voltage is output to the control module based on the bus voltage through the integrated semiconductor tube, and the driving circuit is integrated on the gallium nitride power device, so that the circuit design can be simplified, overcurrent protection and undervoltage protection are simultaneously carried out, and the safety of the gallium nitride totem pole circuit is improved.

The invention belongs to the technical field of circuits, and relates to an output overcurrent protection circuit and method based on a multi-path output flyback high-voltage power supply. According to the invention, the current of the corresponding output branch is acquired in real time through the plurality of output current acquisition circuits; the output over-current trigger circuit is used for comparing the collected current data with a preset threshold value and triggering an over-current protection mechanism once the collected current data exceed the threshold value, and each output branch is provided with an independent output over-current trigger circuit, so that accurate control can be conveniently realized; the over-current protection response circuit is used for gathering all signals output from the over-current trigger circuit, uniformly processing an over-current protection request, and sending an over-current protection signal to the PWM pulse width modulation slow start circuit when the over-current protection request occurs to trigger a power supply protection measure; the PWM pulse width modulation slow start circuit is used for completing soft start of the power supply after output over-current protection occurs in the output branch of any multi-path output flyback high-voltage power supply. And after the soft start is completed, if the current returns to normal, continuing to supply power.

A mainboard protection system and method are provided. A precision resistor is arranged between an overcurrent protection component and a voltage regulator, and the precision resistor is connected to a current monitoring circuit. The current monitoring circuit is connected to a complex programmable logic device, and transmits, w detecting that a voltage difference of the precision resistor is greater than a set threshold, an early-warning signal to the complex programmable logic device. The complex programmable logic device is connected to a processor and sends, when receiving the early-warning signal, an interrupt signal to the processor. in response to receiving the interrupt signal, the processor cuts off outputting of the overcurrent protection component.

The utility model discloses a current metering circuit for a protection board, which comprises a charging and discharging protection circuit, a current acquisition circuit and a controller circuit, and is characterized in that the charging and discharging protection circuit is used for carrying out charging and discharging protection control on a battery; the current acquisition circuit comprises a current sampling resistor R39 and a current signal processing circuit, the current sampling resistor R39 is used for sampling current, and a signal input end of the current signal processing circuit is connected with the current sampling resistor R39 so as to output the sampled current after processing the sampled current; and the controller circuit carries out overcurrent protection control and / or carries out flow statistics output on the current through the charging and discharging protection circuit according to the sampling current. Therefore, a special metering chip is replaced by the independent current signal processing circuit and the controller circuit, so that the implementation of the whole metering function is cheaper, the controller circuit can transmit current metering signals to the outside in a wired or wireless mode, and the application is more flexible.

The invention relates to the field of ceramic materials, provides a high-voltage-resistant PTC (Positive Temperature Coefficient) thermal sensitive ceramic material as well as a preparation method and application thereof, and aims to improve the voltage resistance and PTC effect stability of thermal sensitive ceramic. The material is composed of aluminum oxide-coated manganese-doped barium titanate nanorods, hollow-core silicon dioxide microspheres and a glass phase sintering aid, and the electric heating performance and the microstructure stability are optimized by constructing a core-shell structure and a three-dimensional composite system. A hydrothermal method and a sol-gel method are adopted to precisely control a raw material structure, and alcohol dispersion, tape casting and weak oxidizing atmosphere sintering are combined, so that the compactness and consistency of the ceramic are ensured. The material is suitable for high-voltage temperature control elements and over-current protection devices, and is widely applied to the fields of new energy automobile battery pack over-temperature protection, high-voltage power equipment current limiting elements, industrial automatic temperature control switches and the like.

The invention discloses a high-power magnetron microwave source design method, and belongs to the technical field of microwaves. The advanced series-parallel switch circuit topology technology is adopted, an anode high-voltage power supply, a filament power supply, a control protection unit and the like are integrated, only a connecting port of a transition waveguide and a transmitting antenna is exposed, and the time for mounting the microwave generator is shortened. The stability and reliability of the magnetron are improved, and the service life of the magnetron is prolonged. The LED lamp has comprehensive protection functions of ignition protection, anode overvoltage and overcurrent protection, filament overcurrent and undercurrent protection and the like, has the characteristics of high reliability, safety, high efficiency, high stability, low EMI (Electro-Magnetic Interference) and the like, and has a state display function.

The invention relates to power semiconductor device on-line monitoring and power electronic system control, in particular to a SiC MOSFET conduction current extraction circuit and method, high-frequency oscillation interference is effectively suppressed through a second-order passive RC filter circuit, a measurement error less than or equal to 1.5% is realized within a current range of 50A-300A in combination with an accurate mathematical model established by a depth symbol optimization algorithm, and the measurement accuracy is improved. The requirement of the intelligent gate driver on high-precision current feedback is met, and the measurement precision is remarkably improved; the pulse width direct analysis technology is adopted, a traditional active integrator and a digital decoding link are omitted, the system response delay is smaller than or equal to 500 ns, microsecond-level over-current protection can be supported, the response speed and the real-time performance are optimized, and the system safety in a high-frequency application scene is remarkably improved.

The invention relates to the technical field of charging control, and provides an intelligent control method and system for a high-power charging module, and the method comprises the steps: obtaining a charging state sequence of the charging module, carrying out the feature extraction and mode recognition processing of the charging state sequence, and obtaining a charging safety control parameter; performing hierarchical calculation on the charging safety control parameters to obtain a dynamic safety level, generating an overcharge protection signal and an overcurrent protection signal by using the dynamic safety level, and performing data mapping calculation on the overcharge protection signal and the overcurrent protection signal to obtain a real-time protection strategy; and generating a charging module control instruction according to the real-time protection strategy, and controlling the charging process of the charging module based on the charging module control instruction. Through hierarchical calculation of charging safety control parameters, a charging module control instruction is generated to control a charging process, and the problems of low charging efficiency and poor safety in a scene with a complex charging environment and dynamic demand change are solved.

The invention discloses an energy storage converter and an overcurrent protection circuit and an overcurrent protection method thereof. The overcurrent protection method comprises the following steps: acquiring the equipment temperature and the output current and voltage of the energy storage converter; calculating a current change rate based on the acquired output current; the current real-time temperature is adjusted on the basis of the reference over-current protection threshold value, the voltage collected in real time is applied to the adjusted over-current protection threshold value according to the set proportion, and meanwhile, the current change rate obtained through real-time calculation is applied to the adjusted over-current protection threshold value according to the set proportion. Obtaining a result of a dynamic overcurrent protection threshold value; comparing the dynamic over-current protection threshold value with the output current of the energy storage converter, if the dynamic over-current protection threshold value is exceeded, triggering to execute a protection action, generating a control instruction, and tripping off a switch device for controlling the operation of the energy storage converter; and if not, continuously monitoring and comparing the output current with the dynamic overcurrent protection threshold.

The invention provides a self-checking circuit for overcurrent protection and a self-checking method for overcurrent protection. The signal input end of a self-checking trigger module is connected with the first output end of a control module, and the output end of the self-checking trigger module is connected with the input end of a comparator module; the output end of the comparator module is connected with the input end of the control module; the first input end of the NAND gate module is connected with the second output end of the control module, and the second input end of the NAND gate module is connected with the output end of the comparator module; and the output end of the NAND gate module is connected with the input end of the driving module. During self-checking, the control module controls the self-checking trigger module to output a level signal to the comparator module through a self-checking signal so as to simulate current input, and the comparator module judges whether input level voltage is within a preset range and outputs a comparison result to the control module. The control module can determine the state of the circuit according to the received level signal, and completes the self-inspection of the overcurrent protection circuit.