CN217362575U - Accurate anti-surge impact input overvoltage protection circuit - Google Patents

Accurate anti-surge impact input overvoltage protection circuit Download PDF

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CN217362575U
CN217362575U CN202220912804.9U CN202220912804U CN217362575U CN 217362575 U CN217362575 U CN 217362575U CN 202220912804 U CN202220912804 U CN 202220912804U CN 217362575 U CN217362575 U CN 217362575U
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resistor
circuit
voltage
power supply
input
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徐树友
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Qingyuan Tesla Electronic Science & Technology Co ltd
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Qingyuan Tesla Electronic Science & Technology Co ltd
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    • Y02B20/30Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An accurate surge impact prevention input overvoltage protection circuit comprises a turn-off circuit, a voltage input end and a rear-stage circuit, wherein the turn-off circuit is connected with the voltage input end and the rear-stage circuit and is used for controlling the power supply on-off of the rear-stage circuit; the detection control circuit detects the voltage of the voltage input end in real time, compares the voltage with a set overvoltage protection threshold value, and controls the turn-off circuit to cut off power supply to the rear-stage circuit when the detected voltage is greater than the overvoltage protection threshold value; when the measured voltage is smaller than the overvoltage protection threshold value, controlling the turn-off circuit to be conducted and supplying power to the post-stage circuit; and the rear-stage circuit is used for outputting current to be used by a power supply end and is connected with an energy storage capacitor module, and the energy storage capacitor module supplies power to the rear-stage circuit after the power supply to the rear-stage circuit is cut off by the turn-off circuit. This application can prevent that high-voltage surge from assaulting to cause the damage to components and parts, and response voltage is accurate, and responds rapidly, and the input surge protection of specially adapted power product can in time detect the input peak value under the input surge condition, protects the back stage circuit.

Description

Accurate anti-surge impact input overvoltage protection circuit
Technical Field
The utility model relates to an overvoltage protection field, in particular to accurate surge-proof impact input overvoltage crowbar.
Background
In the switching power supply industry, even if more passive EMC devices are added for protection, when lightning surge occurs, the voltage at the rear end of the EMC devices is abnormally high within a period of time, and the voltage exceeds the upper limit of the voltage which can be borne by a rear-end system device, so that the rear-end system device or a switching power supply control chip, a main switching tube and the like are broken down and damaged. At present, national power grids require upgrading, and in the case of direct-current input voltage, the EMC capability of products is still required. The existing direct current-to-direct current power supply has no EMC protection capability, and even if a front-end EMC circuit is added, the power supply still bears very high bus voltage, so that rear-end equipment or a switching power supply is easily damaged or even is on fire, and huge potential safety hazards exist. The circuit can be arranged in front of the back end of the input end EMC circuit of the input power supply. When surge voltage comes, the input bus voltage can be cut off in time, and the DC-DC power supply is prevented from being damaged.
The method for solving the problem of high voltage after rectification caused by surge voltage of the conventional switching power supply is summarized into three methods:
according to the first front-mounted passive EMC device, samples are reduced, and after surge testing is carried out on the samples, products which are delivered in batches are damaged and even have hidden danger of fire, and the proportion is high;
the second is to increase the upper limit of the range of the working voltage that the power supply can bear, and add more EMC devices. The method has the advantages that the circuit can still normally work when in overvoltage, normal output can be realized within a long time when abnormal input is performed, and the damage is avoided;
and the third is to add an input overvoltage protection circuit, when the over-high voltage of the power grid is detected, the control chip of the switching power supply stops working, or the voltage input of a direct-current bus is cut off, so that the peak voltage resistance of a main switching tube can be effectively reduced, and the main switching tube is protected from being damaged. When the product works outdoors for a long time or is influenced by surge, the reject ratio can be effectively reduced. The circuit has the defects that the existing input voltage peak value circuit has serious temperature drift, and the difference of the acting voltage points at low temperature and high temperature is large.
SUMMERY OF THE UTILITY MODEL
The utility model provides an accurate surge protection circuit of shock input overvoltage protection is provided to the problem that above-mentioned prior art exists.
In order to achieve the purpose, the utility model adopts the following technical measures:
an accurate surge protection input overvoltage protection circuit comprising:
the turn-off circuit is connected with the voltage input end and the rear-stage circuit and is used for controlling the power supply on-off of the rear-stage circuit;
the detection control circuit detects the voltage of the voltage input end in real time, compares the voltage with a set overvoltage protection threshold value, and controls the turn-off circuit to cut off power supply to the post-stage circuit when the detected voltage is greater than the overvoltage protection threshold value; when the measured voltage is smaller than the overvoltage protection threshold value, controlling the turn-off circuit to be conducted to supply power to the post-stage circuit;
and the rear-stage circuit is used for outputting current to be used by a power supply end and is connected with an energy storage capacitor module, and the energy storage capacitor module supplies power to the rear-stage circuit after the power supply to the rear-stage circuit is cut off by the turn-off circuit.
Furthermore, the turn-off circuit comprises a switch tube and a power supply device, a signal control end of the power supply device is connected with the switch tube, a signal end of the power supply device is connected with an MOS tube, a grid electrode of the MOS tube is connected with a driving signal end of the detection control circuit, and a drain electrode of the MOS tube is grounded.
Further, the detection control circuit comprises a resistor R1, a resistor R2 and a resistor R17 which are sequentially connected in series, wherein the resistor R1 is connected with a voltage input end, and the resistor R17 is connected with a signal ground and a detection device U4; the series node of the resistor R17 and the resistor R2 is connected with the sampling end of a detection device U4, the output end of the detection device U4 is connected with the resistor R19, the resistor R19 is connected with the resistor R18 in series, the resistor R18 is connected with the power supply signal input end of the power supply device, and the detection device U4 is connected with the signal ground; the series node of the resistor R19 and the resistor R18 is connected with a base level of a driving triode U6, an emitter of the driving triode U6 is connected with a power supply signal input end, a collector of the driving triode U6 outputs a control signal to the turn-off circuit through a resistor R20, and the resistor R20 is connected with the resistor R17, a detection device U4 and a signal ground through a resistor R21.
Further, the detection control circuit comprises a resistor R1, a resistor R18 and a driving triode U6 which are electrically connected with a voltage input end, the resistor R1 is connected with the resistor R2 and the resistor R17 in series, the resistor R17 is connected with a detection device U4 and a signal ground, a sampling end of the detection device U4 is connected with a series node of the resistor R17 and the resistor R2, an output end of the detection device U4 is connected with the resistor R18 through the resistor R19, a base stage of the driving triode U6 is connected with a series node of the resistor R19 and the resistor R18, and a collector of the driving triode U6 outputs a control signal to the turn-off circuit through the resistor R20.
Further, the resistor R18 is connected to the voltage input terminal through the zener diode ZD 1.
Furthermore, the turn-off circuit comprises a switch tube, the gate of the switch tube is connected with the driving signal end of the detection control circuit, the source of the switch tube is connected with the energy storage capacitor module and the post-stage circuit, the drain of the switch tube is connected with the signal ground, and the gate of the switch tube is connected with the signal ground through a resistor R10.
Further, the energy storage capacitor module is composed of an energy storage capacitor C1, a filter inductor L1 and an energy storage capacitor C2, and the energy storage capacitor C1 is connected with the anode of the energy storage capacitor C2 through the filter inductor L1 to serve as an anode; and the negative electrode of the energy storage capacitor C1 is connected with the negative electrode of the energy storage capacitor C2 to serve as a negative electrode.
Further, the detection device U4 includes an operational amplifier U2, a transistor U5, a diode D6 and a constant voltage source VREF The non-inverting input end of the operational amplifier U2 is connected with the capacitor C2, and the inverting input end of the operational amplifier U2 is connected with the constant voltage source VREF Positive terminal of operational amplifier U2, negative power supply terminal of operational amplifier U2 and constant voltage source VREF The negative terminal of the operational amplifier U2 is connected with a signal ground, the positive power terminal of the operational amplifier U2 outputs a control signal, the output terminal of the operational amplifier U2 is connected with the base of a triode U5, the emitter of the triode U5 is connected with the negative power terminal of the operational amplifier U2 and the anode of a diode D6, and the collector of the triode U5 is connected with the cathode of a diode D6 and the positive power terminal of the operational amplifier U2.
Furthermore, the post-stage circuit comprises a transformer, one end of the initial coil of the transformer is connected with the switching tube, and the other end of the initial coil of the transformer is connected with the energy storage capacitor module.
Further, the surge protection circuit further comprises an EMC filter circuit, and the EMC filter circuit is used for reducing the peak value of the surge input by the voltage input end.
The beneficial effects of the utility model reside in that:
the utility model discloses an accurate surge-proof strikes input overvoltage crowbar, the direct current voltage sudden change after the impact of the voltage of ability real-time detection input, the alternating current input voltage rectification to cut off the power supply for the back level circuit through the control turn-off circuit, prevent that high-pressure surge from strikeing and causing the damage to components and parts, response voltage is accurate, and the response is rapid, and the input surge protection of specially adapted power product can in time detect the input peak value under the input surge condition, protects the back level circuit.
The utility model is suitable for a voltage rising or have various electronic equipment occasions that the surge was strikeed probably appear, lead to the electric wire netting if ground fault etc. the three-phase of voltage abnormity excessive pressure, the single phase alternating voltage input condition, direct current input voltage within photovoltaic 1000 + 2000V direct current input and the multiple occasion of input direct current overvoltage control more than the low pressure 1.25V, the reaction rate is fast, the circuit is simple reliable, with low costs, the superior performance, the design is nimble, can adjust the overvoltage protection threshold value in a flexible way.
Drawings
Fig. 1 is a schematic connection diagram of an embodiment 1 of an accurate surge-impact-prevention input overvoltage protection circuit according to the present invention;
fig. 2 is a schematic connection diagram of a detection control circuit according to embodiment 1 of the present invention;
fig. 3 is a schematic connection diagram of a shutdown circuit according to embodiment 1 of the present invention;
fig. 4 is a schematic connection diagram of a switching tube according to embodiment 1 of the present invention;
fig. 5 is a schematic connection diagram of an energy storage capacitor module according to embodiment 1 of the present invention;
fig. 6 is a schematic connection diagram of a detection control circuit according to embodiment 2 of the present invention;
fig. 7 is a schematic diagram of a detection control circuit according to embodiment 2 of the present invention when the input voltage is lower than the supply voltage of the detection device;
fig. 8 is a schematic connection diagram of a detection device according to embodiment 3 of the present invention;
fig. 9 is a schematic diagram of embodiment 4 of the accurate surge protection input overvoltage protection circuit of the present invention;
fig. 10 is a schematic diagram of another embodiment of an embodiment 4 of an accurate surge protection input overvoltage protection circuit according to the present invention;
FIG. 11 is a graph of DC bus voltage waveform during surge;
fig. 12 is a voltage waveform diagram of the switching tube according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Example 1:
as shown in fig. 1 to 5, an accurate surge impact prevention input overvoltage protection circuit includes a voltage input terminal Vin, a detection control circuit, a rear-stage circuit and an energy storage capacitor module, wherein the turn-off circuit is connected with the voltage input terminal Vin and the rear-stage circuit and is used for controlling the power supply on-off of the rear-stage circuit, the rear-stage circuit is used for outputting current for a power supply terminal and is connected with the energy storage capacitor module, and the energy storage capacitor module supplies power to the rear-stage circuit after the turn-off circuit supplies power to the rear-stage circuit.
The turn-off circuit comprises a switch tube Q1 and a power supply device, the power supply device is a PWM control chip, the power supply device is connected with and drives a switch tube Q1 to output PWM waveforms, the switch tube Q1 is a P-type channel MOS tube, the power supply device has a supply current of more than 0.1mA, the power supply device has a signal control end connected with the switch tube Q1, the power supply device has a signal end connected with an MOS tube Q2, the MOS tube Q2 has a grid connected with the drive signal end of the detection control circuit, and the drain electrode of the MOS tube Q2 is grounded. The MOS transistor Q2 is an N-type channel MOS transistor, the voltage between the drain and the source of the MOS transistor Q2 is usually more than 20V, and the current is more than 100 mA. The input end of the turn-off circuit can be an input positive electrode, and the power supply device is an output negative electrode; the output end of the turn-off circuit is an input cathode or an energy storage capacitor module cathode or an energy storage module anode.
The detection control circuit comprises a resistor R1, a resistor R2 and a resistor R17 which are sequentially connected in series, wherein the resistor R1 is connected with a voltage input end Vin, the resistor R17 is connected with a signal ground and a detection device U4, a series node of the resistor R17 and the resistor R2 is connected with a sampling end of the detection device U4, an output end of the detection device U4 is connected with the resistor R19, the resistor R19 is connected with a power supply signal input end Vcc of the power supply device through the resistor R18, and the detection device U4 is connected with the signal ground; the serial node of the resistor R19 and the resistor R18 is connected with a driving triode U6 base stage, the emitter of the driving triode U6 is connected with a power supply signal input terminal Vcc, the power supply device supplies power to the detection control circuit, and the level output by the power supply signal input terminal Vcc is Vcc level; the collector of the driving triode U6 outputs a control signal to the turn-off circuit through a resistor R20, and the resistor R20 is connected with the resistor R17, the detection device U4 and the signal ground through a resistor R21. The detection device U4 may be a controllable precision regulator or a zener diode.
The detection control circuit detects the voltage of the voltage input end Vin in real time and compares the voltage with a set overvoltage protection threshold value, when the peak value of the bus voltage input at the voltage input end Vin is suddenly increased, the voltage is divided by the resistor R1, the resistor R2 and the resistor R17 and is larger than the overvoltage protection threshold value Vref set in the detection device U4, the anode of the detection device U4 is conducted to the cathode, the junction with the resistor R19 is changed into low level, the resistor R18 and the resistor R19 are divided, the level at the junction with the driving triode U6 is lower than Vcc level, the driving triode U6 is conducted, the driving triode U6 outputs a control signal Vg through the driving resistor R20 and drives the switching MOS tube Q2 to be conducted, at the moment, the control pin of the power supply device is pulled down to the ground potential, the power supply device stops outputting the driving signal, the switching tube Q1 loses the switching function, the voltage input end Vin is disconnected and supplies power to the post-stage circuit, at this time, the maximum voltage between the drain and the source of the switching tube Q1 is the peak value of the bus voltage, there is no switching peak any more, and the voltage of the switching tube Q1 is not greater than the maximum breakdown voltage and is not damaged.
When the voltage input by the voltage input end Vin is normal, the voltage is reduced to be below an overvoltage protection threshold Vref after being divided by the resistor R1, the resistor R2 and the resistor R17, the connection position of the detection device U4 and the resistor R19 becomes a high level, the voltage of the connection position of the resistor R18 and the resistor R19 at the voltage division position and the connection position of the resistance R18 and the driving triode U6 is equal to a Vcc level, the driving triode U6 is disconnected, the control signal Vg is disconnected, the MOS tube Q2 is controlled to be disconnected, and the power supply device restores to normal operation.
Resistance R1, resistance R2, resistance R17 can all select the resistance calorific capacity of high resistance little, and the voltage of voltage input Vin input is normal, MOS pipe Q2 disconnection, and detection device U4 supply current satisfies 1mA and just can normally work, energy-conserving power saving, when voltage input Vin voltage risees unusually, MOS pipe Q2 is in the open mode, power supply device's control foot ground connection, the system is closed, the consumption is littleer this moment, and each circuit element cost among the detection control circuit is not high, therefore, the utility model discloses the circuit has high product practicality and commercial value.
The rear-stage circuit comprises a transformer T, one end of an initial coil of the transformer T is connected with a source electrode of a switch tube Q1, the other end of the initial coil of the transformer T is connected with the energy storage capacitor module, when the voltage of the switch tube Q1 is reduced to be bus voltage, the voltage input end Vin is disconnected to supply power to the rear-stage circuit, and the energy storage capacitor module supplies power to the rear-stage circuit. When this is the case, the back end circuit is powered by the back end capacitor. When the voltage of the energy storage circuit is reduced to be below an overvoltage protection threshold Vref after being divided by a resistor R1, a resistor R2 and a resistor R17, the connection part of a detection device U4 and the resistor R19 becomes a high level, the level of the connection part of the resistor R18 and the resistor R19 and the connection part of the resistor R3583 and a driving triode U6 is equal to Vcc level, the driving triode U6 is disconnected, a control signal Vg is disconnected, a MOS transistor Q2 is controlled to be disconnected, and the power supply device restores to normal work.
In some embodiments, the energy storage capacitor module includes an energy storage capacitor, an anode of the energy storage capacitor is used as an anode of the energy storage capacitor module, a cathode of the energy storage capacitor is used as a cathode of the energy storage capacitor module, one end of the primary coil of the transformer T is connected to the anode of the energy storage capacitor, the anode and the cathode of the energy storage capacitor are respectively connected to the voltage input terminal Vin and the output cathode, the energy storage capacitor has an energy storage function, and can store part of electric quantity when the input voltage increases, and release energy when the voltage decreases.
Specifically, in this embodiment, the energy storage capacitor module is composed of an energy storage capacitor C1, a filter inductor L1, and an energy storage capacitor C2, the energy storage capacitor C1 is connected with the positive electrode of the energy storage capacitor C2 through the filter inductor L1 to serve as a positive electrode, and one end of the primary coil of the transformer T is connected to the positive electrode of the energy storage capacitor module; and the negative electrode of the energy storage capacitor C1 is connected with the negative electrode of the energy storage capacitor C2 to be used as a negative electrode, and the negative electrode is grounded. If voltage input Vin input is the thunderbolt surge, surge duration is within 2S, is supplied power for the back stage circuit by the energy storage capacitor module within 2S, and the power resumes normal output after 2S, and response time is rapider, can reach nS grade, corresponds direct current bus voltage (see figure 11) during the surge, corresponds power switching tube voltage waveform (see figure 12) after adding this circuit during the surge.
The overvoltage protection circuit is flexible and controllable, can be applied to more occasions needing low-voltage direct-current power supply communication power supply, three-phase four-wire power supply, single-phase power supply, photovoltaic power supply, coal mine, wind energy and the like, is effective in weakening surge impact peak values, and can also be applied to a long-time overvoltage state.
Example 2:
as shown in fig. 6, a precision surge protection input overvoltage protection circuit differs from the above embodiment 1 in that: the voltage input end Vin inputs low-voltage direct current, and when the bus voltage input by the voltage input end Vin is ensured to be smaller than the maximum required voltage of the power supply device, the power supply mode of the detection control circuit does not adopt an independent power supply device to supply power.
In detail, the detection control circuit comprises a resistor R1, a resistor R18 and a driving triode U6, wherein the resistor R3578 and the resistor R18 are electrically connected with a voltage input end Vin, a voltage stabilizing diode ZD1 is connected between the resistor R18 and the voltage input end Vin, the resistor R18 is connected with the anode of a voltage stabilizing diode ZD1, and the cathode of the voltage stabilizing diode ZD1 is connected with a bus voltage Vin. The resistor R1 is connected in series with the resistor R2 and the resistor R17, the resistor R17 is connected with the detection device U4 and signal ground, the sampling end of the detection device U4 is connected with the series node of the resistor R17 and the resistor R2, the output end of the detection device U4 is connected with the resistor R18 through a resistor R19, the base level of the driving triode U6 is connected with the series node of the resistor R19 and the resistor R18, and the collector of the driving triode U6 outputs a control signal to the turn-off circuit through the resistor R20. The voltage input end Vin is an input anode, one path of the voltage input end Vin is transmitted to a detection device U4 for sampling comparison, the other path of the voltage input end Vin passes through a voltage stabilizing diode ZD1, and the other path of the voltage input end Vin passes through a resistor R18 and a resistor R19 to supply power to the detection device U4. The zener diode ZD1 can be shorted out when the applied input voltage is lower than the detection device U4 supply voltage (see fig. 7). The voltage input end Vin supplies power to a rear-stage circuit, the turn-off circuit comprises a switch tube Q1, the grid electrode of the switch tube Q1 is connected with a resistor R20 of the detection control circuit, the source electrode of the switch tube Q1 is connected with the energy storage capacitor module and the rear-stage circuit, the drain electrode of the switch tube Q1 is connected with a signal ground, and the grid electrode of the switch tube Q1 is connected with the signal ground through a resistor R10 and can be used as the ground of the short-circuit protection circuit.
The resistor R1, the resistor R2 and the resistor R17 step down the input voltage signal and then supply the voltage signal to the detection device U4, and the detection device U4 can select TL431 of 2.5V or TL432 of 1.25V. When the input voltage is overvoltage, namely when the signal of the voltage input end Vin is overvoltage, the detection device U4 samples that the voltage is higher than the set overvoltage protection threshold Vref to compare, the connection position of the detection device U4 and the voltage R19 becomes low level, the level of the connection position of the resistor R18 and the resistor R19 which divides the voltage and the drive triode U6 is lower than the high level of the anode of the zener diode ZD1, and the drive triode U6 is conducted. After the driving transistor U6 is turned on, the anode high level of the voltage stabilizing diode ZD1 outputs a control signal Vg through the driving transistor U6 and the resistor R20, and controls the switch tube Q1 to be turned off.
When the input voltage is normal, the switching tube Q1 is always in a conducting state, the conducting impedance is small, and there is almost no switching loss, so the heating value is small, and the loss of the detection control circuit is small within 0.1W, and the overall efficiency of the switching power supply is hardly affected. When the input voltage is abnormally increased to 2 times, the switching tube Q1 is in a switching state, the heat productivity is increased, and a proper MOS tube can be selected according to the power consumption.
Example 3
This embodiment is different from any of the above embodiments in that the detection device U4 is a detection control circuit composed of an operational amplifier U2, a transistor U5, a diode D6 and a constant voltage source VREF, see fig. 8.
Further, the detection device U4 comprises an operational amplifier U2, a triode U5, a diode D6 and a constant voltage source VREF The non-inverting input end of the operational amplifier U2 is used as a collecting end, and the inverting input end of the operational amplifier U2 is connected with a constant voltage source VREF Positive terminal of operational amplifier U2, negative power supply terminal of operational amplifier U2 and constant voltage source VREF The negative terminal of the operational amplifier U2 is connected with a signal ground, the positive power terminal of the operational amplifier U2 outputs a control signal, the output terminal of the operational amplifier U2 is connected with the base of a triode U5, the emitter of the triode U5 is connected with the negative power terminal of the operational amplifier U2 and the anode of a diode D6, and the collector of the triode Q2 is connected with the cathode of a diode D6 and the positive power terminal of the operational amplifier U2.
The working principle of the detecting device U4 in this embodiment is the same as that in the above embodiments, and the same effect can be achieved.
Example 4
Referring to fig. 9, a precise surge protection circuit for input, which is different from any of the above embodiments, further includes an EMC filter circuit for reducing a peak value of a surge input from a voltage input terminal Vin.
In addition, a filter circuit is connected between the EMC filter circuit and the rear-stage circuit, and after voltage is input from the voltage input end Vin, the filter circuit filters out ripples in the rectified output voltage.
The EMC filter circuit and the filter circuit can comprise at least one of the following components: the circuit comprises a common-mode ring, an X capacitor, a thermistor, a bridge rectifier, a Y capacitor, a current-limiting resistor, a fuse and a lightning protection discharge tube.
Referring to fig. 10, in another embodiment, a rectifying circuit may be further connected between the EMC filter circuit and the filter circuit, and the rectifying circuit may include at least one of the following components: bridge rectifier, filter capacitor, resistor, diode, etc. the rectifier circuit of filter capacitor changes the alternating current into direct current, and the filter circuit filters out the alternating current component in the voltage.
To sum up, the utility model is suitable for a voltage rising or have surge impact's various electronic equipment occasions probably appear, lead to the electric wire netting if ground fault etc. the three-phase of voltage abnormity excessive pressure, the single phase alternating voltage input condition, direct current input voltage within photovoltaic 1000 supplyes one's power supply 2000V direct current input and the multiple occasion of input direct current overvoltage control more than the low pressure 1.25V, reaction rate is fast, and the circuit is simple reliable, and is with low costs, superior performance, and the design is nimble, can adjust the overvoltage protection threshold value in a flexible way.
The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims (10)

1. An accurate surge protection input overvoltage protection circuit, comprising:
the turn-off circuit is connected with the voltage input end and the rear-stage circuit and is used for controlling the power supply on-off of the rear-stage circuit;
the detection control circuit detects the voltage of the voltage input end in real time, compares the voltage with a set overvoltage protection threshold value, and controls the turn-off circuit to cut off power supply to the post-stage circuit when the detected voltage is greater than the overvoltage protection threshold value; when the measured voltage is smaller than the overvoltage protection threshold value, controlling the turn-off circuit to be conducted to supply power to the post-stage circuit;
and the rear-stage circuit is used for outputting current to be used by a power supply end and is connected with an energy storage capacitor module, and the energy storage capacitor module supplies power to the rear-stage circuit after the power supply to the rear-stage circuit is cut off by the turn-off circuit.
2. The accurate surge-impact-prevention input overvoltage protection circuit according to claim 1, wherein the turn-off circuit comprises a switching tube and a power supply device, a signal control end of the power supply device is connected with the switching tube, a signal end of the power supply device is connected with an MOS tube, a grid electrode of the MOS tube is connected with a driving signal end of the detection control circuit, and a drain electrode of the MOS tube is grounded.
3. The input overvoltage protection circuit for accurately preventing surge according to claim 2, wherein the detection control circuit comprises a resistor R1, a resistor R2 and a resistor R17 which are connected in series in sequence, the resistor R1 is connected with a voltage input end, and the resistor R17 is connected with a signal ground and a detection device U4; the series node of the resistor R17 and the resistor R2 is connected with the sampling end of a detection device U4, the output end of the detection device U4 is connected with the resistor R19, the resistor R19 is connected with the resistor R18 in series, the resistor R18 is connected with the power supply signal input end of the power supply device, and the detection device U4 is connected with the signal ground; the series node of the resistor R19 and the resistor R18 is connected with a base level of a driving triode U6, an emitter of the driving triode U6 is connected with a power supply signal input end, a collector of the driving triode U6 outputs a control signal to the turn-off circuit through a resistor R20, and the resistor R20 is connected with the resistor R17, a detection device U4 and a signal ground through a resistor R21.
4. The accurate surge protection input overvoltage protection circuit according to claim 1, wherein said detection control circuit comprises a resistor R1, a resistor R18 and a driving transistor U6 electrically connected to a voltage input terminal, said resistor R1 is connected in series with a resistor R2 and a resistor R17, said resistor R17 is connected to a detection device U4 and signal ground, a sampling terminal of said detection device U4 is connected to a series node of said resistor R17 and said resistor R2, an output terminal of said detection device U4 is connected to said resistor R18 through a resistor R19, a base of said driving transistor U6 is connected to a series node of a resistor R19 and a resistor R18, and a collector of said driving transistor U6 outputs a control signal to said turn-off circuit through a resistor R20.
5. The input overvoltage protection circuit of claim 4, wherein said resistor R18 is connected to the voltage input terminal through a Zener diode ZD 1.
6. The input overvoltage protection circuit of claim 1, wherein the turn-off circuit comprises a switching tube, a gate of the switching tube is connected to the driving signal terminal of the detection control circuit, a source of the switching tube is connected to the energy storage capacitor module and the post-stage circuit, a drain of the switching tube is connected to a signal ground, and a gate of the switching tube is connected to the signal ground through a resistor R10.
7. The accurate surge-impact-prevention input overvoltage protection circuit according to claim 1, wherein the energy storage capacitor module is composed of an energy storage capacitor C1, a filter inductor L1 and an energy storage capacitor C2, and the energy storage capacitor C1 is connected with the anode of an energy storage capacitor C2 through the filter inductor L1 to serve as the anode; and the negative electrode of the energy storage capacitor C1 is connected with the negative electrode of the energy storage capacitor C2 to serve as a negative electrode.
8. Precise surge protection according to claim 3The surge input overvoltage protection circuit is characterized in that the detection device U4 comprises an operational amplifier U2, a triode U5, a diode D6 and a constant voltage source VREF The non-inverting input end of the operational amplifier U2 is connected with the capacitor C2, and the inverting input end of the operational amplifier U2 is connected with a constant voltage source VREF Positive terminal of operational amplifier U2, negative power supply terminal of operational amplifier U2 and constant voltage source VREF The negative terminal of the operational amplifier U2 is connected with a signal ground, the positive power terminal of the operational amplifier U2 outputs a control signal, the output terminal of the operational amplifier U2 is connected with the base of a triode U5, the emitter of the triode U5 is connected with the negative power terminal of the operational amplifier U2 and the anode of a diode D6, and the collector of the triode U5 is connected with the cathode of a diode D6 and the positive power terminal of the operational amplifier U2.
9. The input overvoltage protection circuit of claim 2, wherein the post circuit comprises a transformer, one end of the primary winding of the transformer is connected to the switching tube, and the other end of the primary winding of the transformer is connected to the energy storage capacitor module.
10. The precision surge-protection input overvoltage protection circuit according to any one of claims 1 to 9, further comprising an EMC filter circuit for reducing a peak value of a surge input at the voltage input.
CN202220912804.9U 2022-04-19 2022-04-19 Accurate anti-surge impact input overvoltage protection circuit Active CN217362575U (en)

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CN202220912804.9U CN217362575U (en) 2022-04-19 2022-04-19 Accurate anti-surge impact input overvoltage protection circuit

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Application Number Priority Date Filing Date Title
CN202220912804.9U CN217362575U (en) 2022-04-19 2022-04-19 Accurate anti-surge impact input overvoltage protection circuit

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