108results about How to "Implement overcurrent protection" patented technology

The invention provides a power switching tube overcurrent detection and overcurrent protection circuit, which comprises an overcurrent detection circuit and an overcurrent protection circuit. The overcurrent detection circuit comprises a sampling tube, a negative feedback circuit, a sampling resistor and a comparator, wherein the gate and source ends of the sampling tube are connected with the gate and source ends of a power switching tube to be detected; the negative feedback circuit can make the drain voltage of the sampling tube tend to be consistent with the drain voltage of the power switching tube; the sampling resistor is used for introducing current flowing through the sampling tube; and the comparator compares the voltage or current of the sampling resistor with an overcurrent reference voltage or current to judge whether the power switching tube has overcurrent or not to realize high-accuracy overcurrent detection. The overcurrent protection circuit comprises a latch used for receiving and latching a detected overcurrent signal, a power switching tube driving circuit and a mirror current tube circuit with a switch. When the switch is switched off, the mirror current tube circuit samples the current of the power switching tube driving circuit, and mirrors the sampled current into the current of the power switching tube to realize the overcurrent protection of the power switching tube.

The invention relates to a control method for switching power supply, whose specific practices are as following: a voltage checking electric circuit (VCC) examines the output voltage V<0> of a converter then delivered to an error amplifier (VA), the error amplifier (VA) carries on the comparison with an output reference voltage V and the output voltage V<0> to get an error voltage value delta V at the start time of each switching period; an error interval judgment (VC) compares the error voltage value delta V with error interval delta n, n=1,2,... N (N=2-5) of the output voltage, control pulse selection signals are outputted to cause a multistage pulse generator (MPG) to generate multistage control pulse with different dutyfactors according to the comparison result, so that the switch tube (TD)of the converter is carried on multistage control. When using the control method, the output voltage ripple of the converter is small, the dynamic response is good, anti-interference capability is strong, and the method is suitable for converters of various topologies.

The invention relates to the technology of power integrated circuit design and discloses an over-current protection circuit aiming at the shortcoming that an over-current protection circuit is susceptible to power tube peak current interference and unreliable in acquired data in the prior art. The over-current protection circuit mainly comprises a current sampling circuit, a reference voltage generation circuit, a voltage comparator and a logic control unit. Current flowing through a power tube is compared with set reference signals to generate over-current information, and control signals are outputted to control the power tube by means of delay. Since the voltage comparator has delayed processing capacity, influences of peak current can be avoided, reliability of over-current acquired data is improved, and misoperations are avoided. The over-current protection circuit is particularly suitable for integrated circuit products of high-voltage heavy-current power management chips, DC-DC converters and the like.

The invention relates to a method for the multi-pulse sequence control of a switch power supply working in a pseudo continuous mode, which comprises the following steps that: a voltage detection circuit (VCC) detects the output voltage V0 of a convertor and transmits the output voltage to an error amplifier (VA); at the beginning time of each switch cycle, the error amplifier (VA) compares an output reference voltage Vref with the output voltage V0 to generate an error voltage value delta V; and an error burst judger (VC) compares the error voltage value delta V with a preset error burst value deltan ( n is an integer from 1 to N) of N(N is more than or equal to 1) output voltages, and outputs a control pulse selection signal according to the result of the comparison to make a multi-pulse generator (MPG) generate control pulses Pn1 and Pn2 with different duty cycles to control the switching tubes S1 and S2 of the a converter TD respectively, wherein the n is an integer from 1 to N+1. The method can realize the multi-pulse sequence control of the switch power supply working in a pseudo continuous mode. The converter adopting the control method has current critical condition limitation-free output power, small output voltage ripples, excellent dynamic response and high disturbance resistance, and is applicable to convertors of various topological structures.

The invention relates to a multilayer discharge gap type surge protection device, which is suitable for overvoltage protection on an alternating-current or direct-current circuit. The multilayer discharge gap type surge protection device comprises n discharge gaps and n-1 trigger circuits, wherein n is an integer of being more than or equal to 2; the n discharge gaps are connected in series to form an overvoltage bleeder circuit; two ends of the overvoltage bleeder circuit are provided with connecting terminals, and the overvoltage bleeder circuit is used for connecting with a protected alternating-current or direct-current circuit; one end of each of the n-1 trigger circuits is respectively connected with a conductive member between the corresponding discharge gaps, and other ends of the n-1 trigger circuits are connected together and connected with the outer end part of the first discharge gap F1; and all the trigger circuits have same structure and are connected in parallel through a capacitor and a resistor to form an RC (Resistor-Capacitor) circuit.

The invention is suitable for the field of charge control, and provides a charger and an over-current protection circuit thereof. The over-current protection circuit comprising a sampling resistor R1, a reference voltage generating unit, a voltage comparing unit and a feedback control unit is arranged in the charger, and the circuit is simple in structure and low in cost; when the short circuit over-current phenomenon occurs in the output end of the charger, feedback voltage in a Boost circuit of the charger can be adjusted rapidly so that the Boost circuit can adjust output currents of the charger according to the feedback voltage, therefore, over-current protection of the charger is achieved, and the charger is prevented from being damaged.

The invention discloses a source driving chip protection circuit, a display panel driving circuit and a display device. The source driving chip protection circuit protects a switching circuit, a current follower and a voltage comparison circuit; and the switching circuit and the current follower are sequentially connected in series between a power management integrated circuit and a source drivingchip. When an adjacent output channel of the source driving chip or the ground is short-circuited and causes a large current generated at a power input terminal of the source driving chip, the current flowing through a second input terminal and a second output terminal of the current follower is correspondingly increased, the voltage of a sampling resistor is greater than a preset reference voltage, and the voltage comparison circuit outputs a switch control signal to control the switching circuit to turn off; therefore, the over-current protection of the source driving chip is realized, andthe source driving chip is prevented from being burnt.

A tester for measuring insulating properties of cross-linked polyethylene, the tester including: a housing including a control panel; a high voltage chamber including an insulating cover, a fixed frame, an insulating oil cup, a high voltage electrode, a ground electrode, and a temperature control device; and a test circuit including a high voltage power supply, a voltmeter, a timer, an overcurrent protection device, and a digital thermometer. The high voltage chamber and the test circuit are arranged inside the housing. The control panel is arranged on the housing. The insulating cover is disposed on the high voltage chamber. The fixed frame is disposed inside the high voltage chamber. The insulating oil cup is mounted on the fixed frame. The high voltage electrode and the ground electrode are disposed oppositely inside the insulating oil cup. The temperature control device is disposed beneath the insulating oil cup.

The invention discloses a start-up overshoot suppression circuit for the LDO. The start-up overshoot suppression circuit comprises a load current detecting unit, a current-voltage converting unit anda voltage comparing unit. The load current detecting unit is connected to the power tube of the LDO for real-time monitoring the amount of the current flowing from the LDO to the load. The current-voltage converting unit is connected in series to the load current detecting unit for converting the current collected by the load current detecting unit into a voltage. The input end of the voltage comparing unit is connected to the current-voltage converting unit, and the output end is connected to the output end of the error amplifier in the LDO, and the voltage comparing unit is used for pullingup the output of the error amplifier according to an output voltage of the current-voltage converting unit to limit the amount of current that the power tube outputs to the load. The start-up overshoot suppression circuit for the LDO realizes the suppression of the overshoot voltage at the start of the LDO with a simpler circuit design, a smaller circuit area and an ultra-low circuit power consumption, thereby realizing a smaller start-up overshoot.

A switching power supply over-current protection circuit includes an alternating-current rectification and filtering circuit, a transformer, a direct-current rectification and filtering circuit, a switching circuit, a control circuit and a feedback circuit; the control circuit comprises a pulse width modulation chip and a sampling resistor. When voltage outputted by the direct-current rectification and filtering circuit is higher a voltage threshold value, the feedback circuit sends a feedback signal to a frequency compensation end of the pulse width modulation chip, such that the potential of the frequency compensation end is pulled low; the pulse width modulation chip compares a current signal collected by the sampling resistor with the voltage of the frequency compensation end; and the output end of the pulse width modulation chip outputs a PWM signal to control the switching on and switching off of the switching circuit, such that the switched-on and switched-off states of the transformer can be controlled, and therefore, stabilized voltage output can be realized. Since the feedback signal is sent directly to the frequency compensation end of the pulse width modulation chip, the feedback signal does not need to pass through a high-gain error amplifier inside the pulse width modulation chip, and therefore, the transmission time of the feedback signal is shortened. The switching power supply over-current protection circuit is advantageous in sensitive response over-current protection and short response time.

The invention discloses an intelligent power supply management system based on a radio frequency identification device (RFID). The intelligent power supply management system based on the RFID comprises an RFID electronic tag installed on an electrical equipment plug, a power supply device used for electrical equipment identification and data collection, and a host machine device used for processing data and commands, wherein the power supply device comprises a power supply device microprocessor unit, an RFID read-write unit, a current detection unit, a power supply device clock unit, a control unit and a power supply device power line carrier communication unit, and the RFID read-write unit, the current detection unit, the power supply device clock unit, the control unit and the power supply device power line carrier communication unit are connected with the power supply device microprocessor unit. The host machine device comprises a host machine microprocessor unit, an embedded webpage unit, a host machine clock unit, a host machine power line carrier communication unit and an electricity utilization history recording unit, wherein the embedded webpage unit, the host machine clock unit, the host machine power line carrier communication unit and the electricity utilization history recording unit are connected with the host machine microprocessor unit. According to the intelligent power supply management system based on the RFID, positions of electrical equipment can be changed freely, and flexibility and practicality of the system are greatly improved.

The invention discloses an overheat and overcurrent protection device, a motor and an overheat and overcurrent protection method thereof. The device comprises a temperature detection unit (10) for detecting the current temperature of an electronic commutation control circuit of a motor to be protected; a biasing unit (20) for converting the current of the motor to be protected at the current temperature into a current overheat feedback voltage of the motor to be protected and transmitting the overheat feedback voltage to a non-inverting input terminal of a comparator (30); and a comparator (30) for outputting a first reverse level signal to a power module of a motor to be protected in a case where the current overheat feedback voltage is greater than a set reference voltage to start an overheat protection mode of the motor to be protected. The scheme of the invention can solve the problem of low reliability of overheat protection caused by slow overheat protection reaction of the chipin the electronic commutation control circuit of the motor, and achieve the effect of improving the reliability of overheat protection.

The invention discloses a traction transformer over current protection method. The method comprises steps: 1) a state of a main circuit breaker connected with a power supply of a target traction transformer is detected and controlled in real time, and when the main circuit breaker is detected to be in a closing state, the second step is carried out; 2) primary current signals of the target traction transformer are acquired, pre-judgment is carried out on the over current state of the target traction transformer according to the value of the acquired primary current signals, and if an over current state is pre-judged, the third step is carried out; and 3) according to similarities of the primary current signals in a former half current period and a latter half current period, the type of the over current state is judged, an over current protection action is not triggered if a magnetizing inrush current generation state is judged, and if a fault over current state is judged, the main circuit breaker is broken, and over current protection is executed. Over current protection misoperation caused by magnetizing inrush current can be avoided, and the method has the advantages of simple realization method, low needed cost, and high over current protection accuracy.

The invention relates to voltage transformer protection technology, specifically to a device for preventing reverse charging of a secondary side of a voltage transformer, and solves the problem that existing voltage transformer protection technology cannot completely prevent a reverse charging phenomenon from occurring in a voltage transformer. The device for preventing reverse charging of the secondary side of the voltage transformer includes a three-phase air switch, a first spring, a lock rod, a support, a lever, a top rod, a bimetallic strip, an electric heating element, a reverse charging release, an overcurrent release, an undervoltage release, and a second spring; a right end of the first spring is fixed to a first phase moving contact of the three-phase air switch; a left part side face of the lock rod is fixed to the first phase moving contact, a second phase moving contact and a third phase moving contact of the three-phase air switch; a right end of the lock rod is provided with a first hook-shaped part; a left end of the lever is provided with a second hook-shaped part which are in a clasp joint with the first hook-shaped part; and a right end of the lever is hinged to the support. The device for preventing reverse charging of the secondary side of the voltage transformer in the invention is suitable for a power grid.

The invention provides an overcurrent protection device which comprises a comparison circuit which is connected to a current sampling element of an intelligent power module and is used for comparing real-time voltage analog signals from the current sampling element with a standard voltage analog signal, and generating corresponding analog control signals according to the comparison results; and an integration circuit which is connected to the comparison circuit and a controller corresponding to the intelligent power module and is used for integrating analog sequence signals from the controller with the analog control signals and outputting the integrated analog sequence signals to the intelligent power module. The invention also provides the intelligent power module and a frequency-conversion household appliance. Through the technical scheme in the invention, overcurrent protection can be achieved more quickly when abnormities, such as interference, cylinder blocking, and voltage sag and the like, occur to the intelligent power module, thereby avoiding the safety hidden trouble due to control delay.

The invention discloses a push-type multifunctional overflow-preventing fuel gas safety valve. The valve comprises a valve casing and a valve joint, wherein the valve casing is made of a non-magnetized material; a magnetic core controller is arranged outside the valve casing; a magnetic core is arranged in a valve cavity; the valve joint is connected to the gas inlet end of the valve casing; the internal cavity of the valve joint is provided with an ultra-flow protective valve for controlling the on-off state of gas flow at the gas inlet end of the valve cavity; the ultra-flow protective valve is provided with a sealing piece for controlling the on-off state of the gas flow; and the sealing piece is provided with a head part which protrudes outward. The push-type multifunctional overflow-preventing fuel gas safety valve is characterized in that: a return magnetic ring is also arranged in the valve cavity and can be controlled by the magnetic pole of the magnetic core controller to move and push the head part of the sealing piece which is in a closed state, so that the ultra-flow protective valve is opened. The push-type multifunctional overflow-preventing fuel gas safety valve has the advantages of capability of causing the return magnetic ring to act by the manual magnetic core controller so as to remove the overflow protection state of the ultra-flow protective valve, fast and accurate return, safe use and high durability.

The invention provides an ultrasonic motor driver. The ultrasonic motor driver comprises a processing module, a two-phase power amplification and matching module, a controllable clock module, a feedback signal collection module and a current detection module; clock signals output from the controllable clock module are output to the two-phase power amplification and matching module to perform matching processing after being processed through the processing module; the clock signals after matching drive the ultrasonic motor to work; the feedback signal collection module feeds back collected speed signals of the ultrasonic motor to the processing module; the processing module processes the feedback speed signals and outputs control signals to the controllable clock module to adjust an output clock of the controllable clock module, so that control targets of motor speed high performance and high stability are achieved.

The invention discloses an intelligent aging rack. The intelligent aging rack comprises a control instrument, a control box and an aging rack body. The control instrument comprises an MCU control module, an indication module, a display module, a PTT signal control module, a warning module, a key module, a control instrument power supply module and a control instrument cable socket, wherein the indication module, the display module, the PTT signal control module, the warning module, the key module and the control instrument power supply module are connected with the MCU control module, the control instrument power supply is used for supplying power, and the control instrument cable socket is connected with the PTT signal control module. The control box comprises a control circuit board, a relay, a PTT signal interface, a PTT signal indicator lamp, a control box power supply module and a control box cable socket, wherein the relay, the PTT signal interface, the PTT signal indicator lamp, the control box power supply module and the control box cable socket are connected with the control circuit board, and the control box power supply module is used for supplying power. The aging rack body comprises a frame, a power supply and a PTT signal control interface, wherein the frame is used for containing aging products, the power supply is used for supplying power to the aging products, and the PTT signal control interface is used for conducting control signal output on the aging products. The intelligent aging rack is compact in structure, safe, reliable, low in cost, capable of achieving dynamic aging by simulating the actual working state of the aging products, capable of monitoring aging process parameters and beneficial for batched aging process.

The invention discloses an offshore floating platform wind, light and oil composite energy power supply system and control method. The system comprises a solar power generation device and a wind power generation device both arranged on an upper deck, and a diesel oil power generation device, a power storage device and an energy control device which are arranged in an equipment compartment. The power storage device is provided with an electric quantity detection unit. The diesel oil power generation device is provided with an oil quantity detection unit. The energy control device comprises a first rectification control unit separately in connection with the solar power generation device and the power storage device; a second rectification control unit separately in connection with the wind power generation device and the power storage device; a third rectification control unit separately in connection with the diesel oil power generation device and the power storage device; and a floating platform power supply and distribution control unit separately in connection with each rectification control unit and the power storage device, and in communication connection with a remote control terminal, and controlling a work mode according to residual electric quantity information, residual oil quantity information, work module information and at least one from control instructions. The system employs a composite energy source, and is suitable for offshore monitoring platforms.

The invention discloses a crest factor overcurrent protection circuit applied to an electronic ballast, and mainly aims to solve the problem that the service life of the electronic ballast is shortened due to no overcurrent protection of a resonant inductor in a resonant network of the conventional electronic ballast. The crest factor overcurrent protection circuit comprises a current sampling circuit, an averaging circuit and a comparison circuit, wherein the averaging circuit is connected between the current sampling circuit and the comparison circuit and is used for averaging transient voltage signals output by the current sampling circuit, multiplying the mean value to obtain an average voltage signal representing an inductive current mean value, and outputting the average voltage signal to the other input end of the comparison circuit; and the comparison circuit compares the average voltage signal with the transient voltage signal output by the current sampling circuit and outputting a crest factor overcurrent protection signal to realize the crest factor overcurrent protection of different inductors. The crest factor overcurrent protection circuit can be used for overcurrentprotection of the electronic ballast and failure detection of a fluorescent lamp.

The invention discloses an anti-magnetic bias circuit and method for an inverter power supply. The circuit comprises a PWM module configured to output a pulse synchronization signal and two original half-wave pulse width modulation signals; a comparison module configured to judge whether a magnetic bias of a main transformer of the inverter power supply occurs; a PWM output control module configured to output a PWM control signal to the PWM module based on the pulse synchronization signal and a comparison result output by the comparison module when a magnetic bias of the main transformer of the inverter power supply occurs; and a PWM pulse width adjusting module configured to generate an anti-magnetic bias pulse width modulation signal having a pulse width larger than that of the originalhalf-wave pulse width modulation signal, and output to an inverter circuit of the inverter power supply to control the magnetic bias state of the inverter power supply. The anti-bias circuit providedby the invention can suppress the magnetic bias state of the main transformer and realize overcurrent protection for a main power tube.

The invention provides an automotive solid-state relay with an NMOS tube and over-current protection. The drain of the NMOS tube is connected with the positive electrode of a vehicle power supply. Thesource is connected with a load. The gate is connected with a boost circuit. The solid-state relay further comprises an MOS tube control circuit connected with the boost circuit. The MOS tube controlcircuit is powered by a solid-state relay control end power supply. The solid-state relay further comprises an over-current protection circuit connected with the MOS tube control circuit. The over-current protection circuit and the NMOS tube are connected in parallel on the drain and the source. After the solid-state relay control end power supply is powered on, the MOS tube control circuit drives the NMOS tube to turn on through the boost circuit. According to the over-current protection circuit, when the NMOS tube is in the over-current condition, the voltage drop of the on-resistance of the NMOS tube in the case of over-current is detected; when the overload current is greater than a threshold, the MOS tube control circuit is turned off; the NMOS tube is turned off to realize over-current protection of the NMOS tube.

The invention provides an automotive solid-state relay with a PMOS tube and over-current protection. The source of the PMOS tube is connected with the positive electrode of a vehicle power supply. Thedrain is connected with a load. The gate is connected with a MOS tube control circuit. The MOS tube control circuit is powered by a solid-state relay control end power supply. The solid-state relay further comprises an over-current protection circuit connected with the MOS tube control circuit. The over-current protection circuit and the PMOS tube are connected in parallel on the drain and the source. After the solid-state relay control end power supply is powered on, the MOS tube control circuit drives the PMOS tube to turn on. When the PMOS tube is in the over-current condition, the over-current protection circuit uses the on-resistance of the PMOS tube to detect the voltage drop in the case of over-current. When the overload current is greater than a threshold, the protection functionis triggered, and the MOS tube control circuit is turned off. The PMOS tube is turned off to realize over-current protection of the PMOS tube.

The invention provides a vehicle-mounted microcontroller, a low dropout regulator and an overcurrent protection circuit of the low dropout regulator. A comparison adjustment unit in the circuit is connected with a sampling unit and a voltage generation unit; the sampling unit is used for sampling breakover current of an adjusting tube in the low dropout linear regulator, converting the sampled breakover current into sampling voltage and outputting the sampling voltage to the comparison adjusting unit; the voltage generation unit is used for generating a comparison reference voltage according to a preset bias voltage and outputting the comparison reference voltage to the comparison adjustment unit; the comparison adjusting unit is used for comparing the sampling voltage with comparison reference voltage and performing feedback control on the grid voltage of the adjusting tube when the sampling voltage and the comparison reference voltage represent overcurrent of the adjusting tube, so as to realize overcurrent protection on the adjusting tube and solve the problem that the output current of the low-dropout linear voltage regulator is too large and the over-current of the low-dropout linear voltage regulator is too high. And the circuit of the low-dropout linear voltage regulator is not functional, so that the reliability of the circuit of the low-dropout linear voltage regulator is improved.

The embodiment of the invention provides a voltage stabilizing device, a protection method and a communication bus power source device, and belongs to the field of electronic technological equipment. The voltage stabilizing device comprises a voltage stabilizing module, a protecting module and a voltage adjusting module. An input end of the voltage stabilizing module is used for being coupled with an external power source, an output end of the voltage stabilizing module is used for being coupled with an input end of the protecting module, an output end of the protecting module is used for being coupled with an external load, a first control end of the voltage adjusting module is coupled with the output end of the protecting module, and a second control end of the voltage adjusting module is coupled with the output end and an adjusting end of the voltage stabilizing module repsectively. After the external load is short-circuit, even if the stabilizing voltage output by the voltage stabilizing module is totally exerted on the protecting module, the power of the protecting module is not bigger than the rate power of the protecting module itself, a circuit cannot be damaged, and further, overvoltage and overcurrent protection for the stabilizing device for a long time can be achieved after the external load is short-circuit. Thus, the functions of overcurrent and overheat protection and the like of the voltage stabilizing device are drastically improved.

The invention discloses a switching power supply circuit, air conditioning equipment and a refrigerator. The switching power supply circuit comprises a driving circuit, a switching power supply module, a detection circuit and an overcurrent protection circuit. The driving circuit generates a driving signal according to the control signal when the control signal is accessed; the switching power supply module converts the input voltage according to the driving signal so as to output a working voltage, wherein the working voltage is used for driving a load; the detection circuit detects a main switch conduction current of the switching power supply module to generate a detection current; the overcurrent protection circuit compares the detection current with a threshold current and generates adisability signal according to a comparison result; the driving circuit stops generating the driving signal according to the disability signal so as to enable the switching power supply module to stop generating the main switch conduction current and the working voltage; and therefore, hardware over-current protection of the load is realized.

The invention discloses an overcurrent protection circuit, a control method, a control device, and a terminal. The overcurrent protection circuit comprises a power switching tube and a voltage dividing circuit, wherein the power switching tube comprises a first power switching tube and a second power switching tube; a first end of the first power switching tube is connected with a third end of thesecond power switching tube, a second end of the first power switching tube is connected with an output end of a terminal power supply, and a third end of the first power switching tube is connectedwith a power supply pin, which is for supplying power to OTG equipment, of a terminal; a first end of the voltage dividing circuit is connected with the power supply pin for supplying power to the OTGequipment, and a second end of the voltage dividing circuit is connected to the ground; a third end of the voltage dividing circuit is connected with a first end of the second power switching tube; and a second end of the second power switching tube is connected to the ground. The overcurrent protection circuit, the control method, the control device and the terminal can effectively solve the problems of short circuit and overcurrent caused by the situation that the OTG equipment is inserted improperly, realize overcurrent protection, improve the reliability and stability of terminal products, and reduce the after-sale maintenance cost.

The invention discloses a voltage control circuit of an air energy water heater. A temperature signal acquiring circuit acquires water temperature signals in an insulation water tank of the air energy water heater; the amplified temperature difference proportion and 0-+5 V diode clamp are obtained through the water temperature signals by a subtractor; and according to the magnitudes of the water temperature signals after clamp, a first-level triode to a fourth-level triode in the voltage control circuit can be conducted and disconnected level by level to change the voltage change ratio of a boosting transformer in a coupling voltage circuit, so that the control of output voltage is realized, and the problems of difficult constant-temperature control, inconvenience in use, low safety and high constant-temperature adjustment cost of a frequency converter in traditional relay-controlling heating are solved. A temperature sensor acquires the temperature signals in the water tank in real time; an operation amplifier performs the subtraction; temperature difference information is output to trigger conduction or disconnection of the corresponding first-level to fourth-level triodes to change the voltage change ratio of the boosting transformer, so that the control over output voltage is realized, the power of a compressor is adjusted, and the water temperature in the insulation water tank is in a constant-temperature state; and the voltage control circuit of the air energy water heater is simple, practical and low in cost.

The invention provides an overcurrent protection circuit and a method, a clock signal generation circuit and a display device. The overcurrent protection circuit comprises N first over-current detection circuits, N second over-current detection circuits, a first signal generation circuit, a second signal generation circuit, a first level conversion circuit, a second level conversion circuit and acontrol circuit. The first signal generation circuit is used for outputting a first control signal to the first level conversion circuit when receiving a first overcurrent indication signal; the second signal generation circuit is used for outputting a second control signal to the second level conversion circuit when receiving a second overcurrent indication signal; the control circuit is used forproviding a turn-off control signal for the n output control module within a preset time after receiving the third control signal and / or the fourth control signal; wherein N is a positive integer, and n is a positive integer smaller than or equal to N. According to the invention, the overcurrent protection of the clock signal generation circuit can be realized only by adopting two level conversion circuits.