132results about How to "Suppress surge current" patented technology

The invention discloses a fault isolation electronic switch applicable to a direct current power supply system of a spacecraft, comprising a power MOS (Metal Oxide Semiconductor) tube M1 for power transmission control, a resistor R0 for current detection, a continuous current diode D1 for providing a continuous current circuit, a power driving circuit with slow power-on and power-off functions for inhibiting surge current and peak voltage, a delay tripping circuit for realizing an inverse time limit protection function of a circuit and an isolation control circuit for transferring state and control information. The output of the power driving circuit with slow power-on and power-off functions enters into logic control, and the power-on / power-off of the power MOS tube M1 is controlled, so that a solid power electronic switch is controlled; the output of the delay tripping circuit enters into logic control to generate a driving signal, and the power-on / power-off of the power MOS tube M1is controlled, so that immediate inverse time limit protection is realized; and an input / output signal of the isolation control circuit is electrically isolated from a power circuit. A slow power-on and power-off technology is adopted in the power driving circuit provided by the invention, thus, the surge current and the peak voltage caused by a capacitive load and an inductive load can be effectively inhibited, the loading capacity of the electronic switch can be improved, and safe, stable and reliable work of equipment can be guaranteed.

The invention relates to a novel power-on surge current suppression circuit. The novel power-on surge current suppression circuit comprises a power supply circuit, a surge current suppression resistor end voltage sampling and comparison circuit, a relief resistor, a metal oxide semiconductor (MOS) transistor, a surge current suppression resistor and an optional small-capacity high-frequency filtering capacitor, wherein the power supply circuit comprises a rectification diode, an energy storage filtering capacitor and a buck voltage limitation circuit, the surge current suppression resistor end voltage sampling and comparison circuit comprises a first end voltage sampling resistor, a second end voltage sampling resistor, a reference voltage source and a comparator, a drain of the MOS transistor is connected with a DC-DC converter, a source of the MOS transistor is connected with a negative end of a rectifier bridge, a grid of the MOS transistor is connected with an output end of the power supply circuit, an input end of the power supply circuit is connected with an AC N / L end, the surge current suppression resistor is connected in parallel to the drain and the source of the MOS transistor, the relief resistor is connected in parallel to the grid and the source of the MOS transistor, and the optional small-capacity high-frequency filtering capacitor is connected between a positive end and the negative end of the rectifier bridge. With the power-on surge current suppression circuit disclosed by the application, the power-on surge current is suppressed better, the power consumption of an MOS transistor driving circuit is low, the starting speed is fast, and the power-on time allowed again is short.

The invention discloses a power-switch switching circuit, which comprises a field effect transistor and a control circuit, wherein, the field effect transistor is used for switching on or switching off under the control of a stepping control voltage, and comprises a grid electrode, a source electrode and a drain electrode; the grid electrode is connected with the stepping control voltage, the drain electrode is connected with an input terminal of a power supply, and the source electrode is connected with an output terminal of a load; the control circuit is used for synthesizing two control voltages which are input by the input terminal of the control circuit to form and output the stepping control voltage through the control of a logic control signal; the control circuit is connected with the grid electrode of the field effect transistor. In the power-switch switching circuit, the stepping control voltage is used for charging the grid electrode of the field effect transistor, surge current which is generated when the field effect transistor is conducted can be restrained through the control of the stepping control voltage, so the circuit works stably under the control of a power-switch, and devices are not easy to be damaged; in addition, because the circuit adopts one field effect transistor only, the cost is low and the volume is small.

The invention provides an LDO (low dropout regulator) provided with a slope starting circuit. The regulator comprises the starting circuit (201) and a main regulator circuit (202), wherein on one hand, the starting circuit (201) is used for generating two channels of slope enabling signals EN and EN_b to serve as input signals at an enabling end of the main regulator circuit, on the other hand, the starting circuit is used for outputting a voltage signal Vro to serve as input of the main regulator circuit, and the voltage signal Vro rises in a slope manner and is finally stabilized at certain voltage value; the main regulator circuit (202) is used for proportionally amplifying the voltage signal Vro and outputting stable voltage Vo under the control of the two channels of slope enabling signals EN and EN_b. The LDO can effectively prevent surge current during power-up starting and consumes quite little current.

The invention discloses a base region gradient P<+>-N-N<+> type SiC ultrafast recovery diode manufactured on a 4H type single crystal silicon carbide epitaxial layer and a process. An anode / (P<+>)4H-nc-SiC / (N) slowly changes into a 6H-nc-SiC / (N)4H-c-SiC / (N<+>)4H-c-SiC / cathode. The base region gradient P<+>-N-N<+> type SiC ultrafast recovery diode comprises an N<+> type 4H-c-SiC substrate, an N type 4H-c-SiC epitaxial layer, an N type 6H-nc-SiC gradually-doped and grain-gradient multilayer film and a P<+> type 4H-c-SiC single layer film, wherein the outer sides of the N<+> type 4H-c-SiC substrate and the P<+> type 4H-c-SiC single layer film are in ohm connection with an anode NiAu and an anode TiAu respectively. The device structure is made by using a PECVD (Plasma Enhanced Chemical Vapor Deposition) technology. The process has the advantages of shortening the reverse recovery time, inhibiting surge current and lowering the process temperature.

The invention discloses a power tube driving control circuit suitable for a solid-state power controller. The power tube driving control circuit comprises a switch-on / off circuit, a driving protection circuit, a transient suppression circuit, a slow switch-on circuit, a current sampling circuit, a freewheeling diode D2 and an MOS (Metal Oxide Semiconductor) transistor M1. Through adoption of the power tube driving control circuit, wrong switch-on / off actions of the MOS transistor M1 caused by a wrong power-on sequence can be avoided, and the problems of poor capacitive load capacity, high dependence on a parasitic parameter, failure in normal startup due to large transient current, and the like in an existing solid-state power controller are solved.

The invention discloses a rear preregulator DC / DC converter which is mainly used for realizing preliminary adjustment of voltage waveform output by a power transformer and achieving a purpose of multiple output of large current. The rear preregulator DC / DC converter mainly comprises a surge inhibition circuit (1), filters (2) and (4), a main power loop (3), a main control circuit (5), a phase synchronous circuit (6) and a rear regulation and control circuit (7). The surge inhibition circuit (1) realizes limit on surge current when being started, the filters (2) and (4) realize filter of the circuit and reduce EMI (Electro-Magnetic Interference) of the converter, the main power loop (3) completes change and isolation of input and output voltages, the phase synchronous circuit (6) realizes a drive pulse that the rear regulation and control circuit (7) is synchronous with the main control circuit (5), and a rear regulation circuit (8) completes the regulation of the output voltage. All inductors and transformers in the converter are realized by adopting a multilayer PCB (Printed Circuit Board) transformer technology.

The invention discloses an NTC (Negative Temperature Coefficient) thermistor material with a high B value and a high stability and a production method thereof. The NTC thermistor material is characterized by comprising the following raw materials by weight percent: 30-45% of Co, 15-25% of Fe, 1-8% of Al, 0.1-0.5% of Cu, 0.1-0.5% of Nd, 0.05-0.4% of Zr, and the balance of Mn. According to the production method, the raw materials are placed into a ball-milling device and are subjected to the processes of wet ball milling, pre-sintering, molding, sintering, and the like, thereby obtaining the end products. The production method of powder wet-mixing and secondary ball-milling is adopted, so that the material constant B value of the thermistor material is greatly increased; the material constant B value can reach up to 4500K; and an NTC thermistor made of the NTC thermistor material provided by the invention has the characteristics of high sensitivity, high response speed, stable performance and excellent interchangeability, and can be widely applied to the situations, such as temperature measurement, temperature compensation, surge current restraining, and the like.

The invention discloses a surging current suppression method, which belongs to the application technology of device power ports. The method is formed as follows: at least one surging current suppression circuit is in series connection between an electric equipment power port and a commercial power, and large current impacts produced when electric equipment is started routinely can be effectively suppressed by adjusting impedance of an electric equipment power terminal through the surging current suppression circuit. The surging current suppression method can simultaneously guarantee power supply quality of a power network, avoid producing severe electromagnetic interference and not affect other properties of equipment while effectively suppress surging current.

The invention relates to a spaceborne integrated storage battery discharge switching circuit, which comprises a switching circuit, a signal control circuit and a surge current control circuit, and is characterized in that the switching circuit is connected between a storage battery pack and a discharge circuit in series, the switching circuit comprises a first discharge switch, a second discharge switch and a third discharge switch which are connected in parallel, a source electrode of each discharge switch is connected with the storage battery pack, and a drain electrode of each discharge switch is connected with the discharge circuit; an input end of the signal control circuit is connected with a switching control signal, an output end of the signal control circuit is connected with a grid electrode of the first discharge switch in the switching circuit, and the signal control circuit is used for controlling on-off of the first discharge switch in the switching circuit; and an input end of the surge current control circuit is connected with the discharge circuit, an output end of the surge current control circuit is connected with a grid electrode of the second discharge switch and a grid electrode of the third discharge switch in the switching circuit, and the surge current control circuit is used for controlling on-off of the second discharge switch and the third discharge switch in the switching circuit and eliminating surge current. The spaceborne integrated storage battery discharge switching circuit not only improves the reliability and the power mass ratio of a storage battery pack discharge switching circuit and reduces the volume and the weight of the system, but also improves the integrated design level of a power supply subsystem.

The invention relates to a power protection circuit preventing controlled silicon effect, used for a power input end of a circuit and based on a constant flow source. By using the feedback principle and the principle that the voltages at both ends of a capacitor can not jump and adding a momentary cutoff function, when the circuit produces the controlled silicon latch-up effect, the power protection circuit can momentarily cut off the power supply source of a circuit board so as to destroy the maintenance current condition required by the controlled silicon and thoroughly eliminate the controlled silicon effect, which can effectively suppress the start-up surge current. When the controlled silicon effect is eliminated, the power protection circuit can quickly recover the normal power supply to the circuit board. The method provides effective protective measures for the load short circuit at the same time. When the load short circuit happens, an extremely low current is provided. The circuit has the advantages of simple structure and easy implementation.

The invention discloses an intelligent building electric power distribution device, which comprises a main circuit which supplies electricity for buildings, wherein the output end of the main circuit is connected with an energy-saving composite control circuit which is connected with a power distribution circuit which supplies electricity for each electrical appliance and a direct current voltage stabilizing circuit which supplies electricity for the energy-saving composite control circuit. The energy-saving composite control circuit mainly comprises a straight-through or power-saving control circuit and a power-saving shifting control circuit. The intelligent building electric power distribution device not only can satisfy the requirement of low-voltage distribution, but also can filter clutter, optimize power supply parameters, improve power consumption efficiency, reduce the waste of residual or excess electric energy, maximally save electric energy through the automatic adjustment of the power-saving shifting control circuit under the circumstance of guaranteeing the normal work state of electric equipment, thereby saving the expenditure of electricity charge, and the power saving rate is generally between 15% and 25%.

The invention discloses a lightning protection device applicable to an RS-485 transmission line. A primary lightning protection circuit is realized by a GDT (gas discharging tube); a first inductor L1 and a first thermistor PPTC1 in a secondary lightning protection circuit are connected in series and are then connected onto an A connecting wire of an RS-485 bus; a second inductor L2 and a second thermistor PPTC2 are connected in series and are then connected onto a B connecting wire of the RS-485 bus; a first transient suppression diode TVS1 in a tertiary lightning protection circuit is in span connection between the A wiring end and the B wiring end of the RS-485 bus; a second transient suppression diode TVS2 and a third transient suppression diode TVS3 are connected in series and are then in span connection between the A wiring end and the B wiring end of the RS-485 bus. The lightning protection device has the advantages that in the lightning attack protection process, lightning protection devices per se are complete and are not damaged; high anti-electromagnetic interference capability is realized; in addition, the sufficient fast response speed is realized on the lightning attack.

The invention discloses a multiphase motor channel fault ride-through operation control method. With the multiphase motor channel fault ride-through operation control method adopted, when a certain orseveral channels fail, fault-tolerant on-line channel switching non-stop ride-through operation is realized; and during a process in which the channel fails or the failed channel is removed, the over-current protection of the inverter alternating-current side (motor winding side) of the remaining operating channels, the voltage stabilization control of the inverter direct-current bus-bar side ofthe remaining operating channels and inverter magnetic field compensation integrated coordination control are implemented. With the method adopted, fast, stable and safe fault-tolerant on-line channelswitching non-stop ride-through operation of a multiphase motor is realized. The method can be used for high-power electromechanical energy conversion occasions such as ship propulsion, track traction and wind power generation.

The invention provides a wireless electric energy transmission system and a wireless electric energy transmission method. Through setting a multi-stage start circuit, a surge current of a transmitting terminal power frequency rectification filter circuit in a powered-on state is inhibited; through step-by-step opening of a duty ratio carried out by a transmitting terminal MCU, a surge current of an LC resonance circuit on an inversion loop is inhibited; through controlling an opening time sequence of a back-stage BUCK voltage stabilizing circuit, influence of load switching on system start is inhibited. The method is advantaged in that problems of the surface currents of the transmitting terminal power frequency rectification filter circuit and the LC resonance inversion circuit in the powered-on state and system stability and reliability of load switching in a start process can be effectively solved.

The invention provides a surge current suppression circuit. After the suppression circuit is electrified, an alternating-current power supply charges a C1 via a D1, a D2, an R1, an R2 and an R3. The voltage of the C1 is stabilized to be the clamping voltage of a voltage-regulator tube ZD1. The positive-end level of the C3 is the input voltage after rectification, the waveform is the sine half-wave and the C3 does not have charging access. The voltage of the C3 is 0, thus, the negative end level of the C3 changes along with the positive-end voltage and change conditions of the power voltage is directly reflected. Before the power voltage is lower than the Q1 operating voltage, a Q1 and a Q2 are kept in the turned-off state. When the power voltage changes to be lower than the Q1 operating voltage, the power level state is reflected by the negative-end level of the C3 and then the Q1 is conductive. Current flows into the grid electrode of the Q2 via the Q1 and an R6 from the C1, so level of the Q2 is increased and exceeds the open threshold voltage, and the Q2 is conductive. When the power voltage charges the C3 via the Q2, the instantaneous value of the power voltage is quite low and the surge current can be suppressed.

The invention provides a soft start circuit used for a DC-DC converter, and belongs to the technical field of electronic circuits. In a soft start stage, the slope voltage VSS_OUT is compared with the division voltage VFB of output voltage, so output of the soft start is achieved. The slope voltage VSS_OUT is increased with a quite high slope rate k1, so establishing time of the soft start is shortened. When voltage on two ends of a first capacitor C1 reaches a threshold value voltage of a first NMOS tube M1, the rising slope rate of the slope voltage Vss_out is reduced to k2, thereby protected inductor current against overshooting. After the soft start is finished, i.e., the slope voltage VSS_OUT exceeds the reference voltage VREF, an additional charging branch is started, the grid electrode voltage VSS of a fourth NMOS tube M4 is quickly set to be close to the level of a power supply, the slope voltage VSS_OUT quits, and the reference voltage VREF is input in the positive input end of a comparer. According to the invention, slow rising of output is ensured at the soft start stage; the rising slope rate of the slope voltage Vss_out is quite high in the beginning; the establishing time of the soft start is shortened; and then the rising slope rate is reduced, so the occurrence of the surging current is inhibited.

The invention relates to spaceborne electronic equipment, and discloses a protective device for inhibiting a power-on surge current. The protective device comprises a surge inhibiting circuit which is formed by arranging an input end overcurrent protective circuit [101] at a power switch end and arranging an integrating circuit [102], a power amplifying circuit [103], a common mode filter [104] and a differential mode filter [105] in sequence after the overcurrent protective circuit [101]; and the surge inhibiting circuit is connected with subsequent electronic equipment through a coupling transformer. By using the protective device, damage or misoperation of a product and even the influence on normal work and the like because of the electromagnetic induction of a starting current of other equipment caused by the power-on surge current of a switching power supply are avoided. The protective device has the advantages of simple design, and stability and reliability at work. The quality and the performance of power supply are improved.

The invention relates to a phase-splitting control high and low-voltage switch electric appliance and method of controlling, the electic appliance includes a controller connected to the on-off electrical equipment, wherein the controller includes a three-phase voltage-current detecting circuit, a voltage-current phase-locked loop frequency doubling clock circuit, a microcontroller, an self-adapting on-off status detecting circuit and execution unit, wherein the three-phase voltage-current signal is inputted by voltage-current through zero passage detecting circuit, the voltage-current phase-locked loop frequency doubling clock circuit and the microprocessor unit to the execution unit for output, and the self-adapting on-off status detecting circuit feeds back the signal to the micro controller.

The invention provides a soft starting circuit, a soft starting method and a DC charging pile. The soft starting circuit comprises a controller, a rectifying module, a first switch, a second switch and a backflow prevention diode, wherein the controller acquires measured values of three detection points in real time, and obtains charging voltage and current information of a battery pack from a vehicle battery management system BMS; the first detection point detects voltage between a positive output end and a negative output end of the rectifying module, the second detection point detects voltage between output positive and negative ends of the charging pile, and the third detection point detects output current of the charging pile and the rectifying module; and the controller adjusts the output voltage and current of the rectifying module and controls the on-off time sequence of the first switch and the second switch, so as to avoid the occurrence of surge current in the process of starting the charging. The soft starting circuit, the soft starting method and the DC charging pile effectively suppress the surge current at the time of starting the charging, avoid the damage to electrical devices caused by the impact of the surge current, and avoid the adhesion of contacts of the switching devices through controlling the time sequence of the switching devices.

The invention discloses a high power pulse load power soft start device and a starting method; the high power pulse load power soft start device comprises a MOS tube Q1, a MOS tube Q2, a MOS tube Q1 control device and a MOS tube Q2 control device, wherein the MOS tube Q2 control device comprises a voltage sampling circuit, a comparator and a driver circuit, which are connected in sequence; the voltage sampling circuit comprises a resistor RS1 and a resistor RS2; the resistor RS1 and the resistor RS2 are connected in series and then are connected to two ends of an energy-storage capacitor C; the input end of the comparator is connected between the resistors RS1 and RS2; the drain electrode of the MOS tube Q2 is connected to one end of the energy-storage capacitor, and the source electrodeis connected to the negative pole of a direct-current bus; the MOS tube Q1 control device comprises resistors R1, R2, R3 and a direct-current power supply; the drain electrode of the MOS tube Q1 is connected to one end of the energy-storage capacitor, the source electrode is connected to the cathode of the direct-current bus through the resistor R1, and the grid electrode is connected to the direct-current power source through the resistor R2; and the grid electrod3 of the MOS tube Q1 is also connected to the cathode of the direct-current bus through the resistor R3. The high power pulse loadpower soft start device and the starting method in the invention has good surge current suppression effect, simple circuit and small loss, and is suitable for high power applications.

The invention discloses a dual-purpose switching circuit for preventing reverse connection and suppressing boot surge current, which comprises a delay circuit, a driving circuit, a switching device and a reverse-connection-proof and surge-suppressing circuit. The output end of the delay circuit is connected with the input end of the driving circuit, the output end of the driving circuit is connected with the switching device, and the anti-reverse connection and surge suppression circuit are connected in parallel with the switching device. The inrush current suppression circuit and the anti-reverse connection circuit are combined together. Compared with the prior art scheme in which the electromagnetic relay is used as the switching element, the circuit is small in size, and and the drive circuit is simple and reliable; Compared with the scheme of controlling the conduction state of the MOS transistor to suppress the inrush current, the circuit is more suitable for medium and high poweroccasions due to the limited dissipation power of the MOS transistor, and does not need to accurately control the conduction state of the MOS transistor. The invention has the characteristics of small volume and simple and reliable driving circuit.

The invention discloses an input overvoltage protection circuit with a powered inrush current restraining function. The input overvoltage protection circuit comprises a power supply circuit, a peak detection circuit, a peak voltage sampling comparison circuit, a powered moment switching tube current sampling comparison circuit, a bleeder resistor, a low on-resistance switching tube and a referencevoltage source; the power supply circuit comprises a first diode, a first capacitor and a voltage limiting biasing circuit; the peak detection circuit comprises a second diode and a second capacitor;the peak voltage sampling comparison circuit comprises a first comparator, a first resistor and a second resistor; and the powered moment switching pipe current sampling comparison circuit comprisesa second comparator, a third resistor and a fourth resistor. Therefore, the input overvoltage protection circuit is rapid in overvoltage protection action, and can restrain powered inrush current; theovervoltage protection circuit and the powered inrush current restraining circuit are organically combined to share a power switching tube and the power supply circuit, and thus the number of elements is small and the cost is low. The input overvoltage protection circuit not only solves the problem of input overvoltage protection difficulty, but also restrains the powered inrush current.

The invention relates to a quick power-down device, in particular to a quick power-down module of low-voltage equipment. The quick power-down module comprises a switch field-effect tube, a drive field-effect tube, a capacitor CE1, a resistor R1, a resistor R3 and a resistor R4. According to the quick power-down module of the low-voltage equipment, quick breakover and quick disconnection can be achieved when the drive field-effect tube is powered on or powered off through the capacitor CE1, the adjustable resistor R3 and the resistor R4, due to the fact that the resistor R3 is adjustable, different drive field-effect tubes can be precisely adjusted to the threshold voltage of the drive field-effect tubes, meanwhile, the switch field-effect tube is started slowly when the circuit input end is powered on through the capacitor C1, the resistor R1 and the resistor R2, and the switch field-effect tube is protected from being broken down by the inrush current in the power-on process.

The invention discloses a surge current suppression circuit and method, and the suppression method employs the surge current suppression circuit for suppression. The surge current suppression circuitcomprises a charging circuit and a digital control chip, and the charging circuit is used for obtaining an alternating current and charging an output capacitor; the charging circuit comprises a thyristor and a driving circuit, and the gate end of the thyristor obtains conduction driving voltage from the alternating current line through the driving circuit; a pulse type charging control program isconfigured in the digital control chip, and the pulse type charging control program is used for controlling the charging circuit to perform pulse type charging on the output capacitor according to theconduction interval modulation program and the conduction time point determination program; and the conduction interval modulation program is used for modulating the conduction interval of the thyristor to be conducted only in the absolute value reduction interval of the input alternating-current voltage. The influence of the environment temperature on the surge current suppression effect is overcome, and the structure is simple and ingenious.

The invention provides a preparation method of a chromium and manganese co-doped perovskite type negative temperature coefficient heat-sensitive ceramic material. The method comprises the following step: weighing the following raw materials: 20-55% by atom of La, 5-75% by atom of Cr and 5-40% by atom of Mn; performing wet milling to obtain slurry; drying and grinding the slurry to obtain powder; roasting to obtain perovskite-phase La(CrMn)O3 powder; preparing the powder into block materials; performing two-step sintering method; cooling with the furnace to obtain the chromium and manganese co-doped perovskite type negative temperature coefficient heat-sensitive ceramic material. The chromium and manganese co-doped perovskite type negative temperature coefficient heat-sensitive ceramic material prepared according to the method has the advantages that electrical parameters are that rho25 DEG C=15.2 omega.cm-13823.2 ohm.cm+ / -2%, B25 / 50=2688-3942K+ / -1.5%; the material has the characteristics that the high-resistance, low-B and low-resistance and high-B parameter combination is realized; the consistency is high; the stability is high; the material is recyclable; the material is applicable to measuring and controlling of temperature in wide temperature range, circuit compensating and inhibiting of surge current.

The invention discloses a lightning arrester internal monitoring method and system, and the method comprises the steps: collecting a leakage current in a lightning arrester through an electricity taking valve plate, outputting the leakage current to an electricity taking module, wherein the electricity taking module intermittently supplies power to a lightning arrester monitoring system; a measurement module measures the leakage current of the lightning arrester, and sends a lightning stroke trigger signal to the power taking module and the single-chip microcomputer when the lightning arresterpasses through the impact current to trigger the power taking module to supply power, and the single-chip microcomputer records the lightning stroke action; the sensor measures information such as temperature, humidity and air pressure in the lightning arrester cavity; the single-chip microcomputer and the communication module acquire data of the measurement module and the sensor and remotely transmit the data to the server; the server displays leakage current, lightning stroke action records, temperature, humidity and air pressure information of the lightning arrester through the acquired data and analyzes the state of the lightning arrester. According to the invention, the lightning arrester leakage current, the resistive component, the action frequency, the internal temperature and humidity and the air pressure data can be automatically acquired through the lightning arrester leakage current, the whole set of device can be integrated in the lightning arrester cavity, and the integration of the lightning arrester, monitoring and power acquisition is realized.

The invention discloses an anti-surge circuit comprising a high-power resistor R1, an MOS tube Q1, a resistor R2, a resistor R3, a resistor R4, a voltage-regulator tube ZD1, a capacitor C1, an electrolytic capacitor EC1, a capacitor C3, a capacitor C2, a bridge pile BD1, and a fuse F1. The anti-surge circuit is characterized in that one end of the capacitor C1 is connected with the positive electrode of the electrolytic capacitor EC1, one end of the resistor R4 and the positive electrode of the bridge pile BD1; the other end of the capacitor C1, the negative electrode of the electrolytic capacitor EC1, the drain of the MOS tube Q1 and one end of the resistor R1 are grounded; the other end of the resistor R1 is connected with the negative electrode of the bridge pile BD1, the source of the MOS tube Q1, one end of the capacitor C2, the anode of the voltage-regulator tube ZD1, one end of the capacitor C3 and one end of the resistor R3; the other end of the capacitor C2 is connected with the gate of the MOS tube Q1, the cathode of the voltage-regulator tube ZD1 and one end of the resistor R2; and the other end of the resistor R2 is connected with the other end of the resistor R4, the other end of the resistor R3 and the other end of the capacitor C3. The surge current can be suppressed for both fast switching on / off and heat engine switching on / off, and therefore, the impact of electronic products to the power grid is reduced greatly.