CN214153994U - Overvoltage protection circuit and device - Google Patents
Overvoltage protection circuit and device Download PDFInfo
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- CN214153994U CN214153994U CN202120157628.8U CN202120157628U CN214153994U CN 214153994 U CN214153994 U CN 214153994U CN 202120157628 U CN202120157628 U CN 202120157628U CN 214153994 U CN214153994 U CN 214153994U
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Abstract
The utility model discloses an overvoltage crowbar and device, including voltage detection circuit and control circuit. The voltage detection circuit is used for detecting the power supply voltage of the input power supply of the device; the control circuit is used for cutting off a power supply line of the input power supply of the device when the power supply voltage is larger than a preset overvoltage threshold value. Therefore, the power supply circuit of the device can be cut off when the power supply voltage of the input power supply of the device is larger, so that the rear end circuit of the device is prevented from being burnt, and the safety and the reliability of the device are improved.
Description
Technical Field
The utility model relates to a device safety protection field especially relates to an overvoltage crowbar and device.
Background
At present, the input power of most devices (such as charging devices of electric automobiles) adopts alternating current input, and then the alternating current input is subjected to rectification, filtering, voltage reduction and the like to supply power to working parts in the devices. However, the input power of the device is sometimes unstable, which may cause overvoltage risk, and if serious, may burn out the back-end circuit of the device, thereby reducing the safety and reliability of the device.
Therefore, how to provide a solution to the above technical problem is a problem that needs to be solved by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an overvoltage crowbar and device can cut off its power supply line when the supply voltage of device input power is great to prevent that device rear end circuit from being burnt, thereby improved the security and the reliability of device.
In order to solve the technical problem, the utility model provides an overvoltage protection circuit, include:
the voltage detection circuit is connected with the power supply end of the device input power supply and is used for detecting the power supply voltage of the device input power supply;
and the control circuit is connected with the output end of the voltage detection circuit and is used for cutting off a power supply line of the input power supply of the device when the power supply voltage is greater than a preset overvoltage threshold value.
Preferably, the voltage detection circuit includes:
the voltage mutual inductance circuit is connected with the power supply end of the device input power supply and is used for carrying out voltage reduction processing on the power supply voltage of the device input power supply to obtain a voltage reduction signal;
the signal amplification circuit is connected with the output end of the voltage mutual inductance circuit and is used for carrying out signal amplification processing on the voltage reduction signal to obtain a voltage amplification signal;
the peak detection circuit is connected with the output end of the signal amplification circuit and is used for detecting the peak value of the voltage amplification signal to obtain a voltage peak value signal;
and the RC circuit is connected with the output end of the peak detection circuit and is used for filtering and rectifying the voltage peak signal to obtain a voltage effective value and supplying the voltage effective value to the control circuit.
Preferably, the voltage transformer circuit comprises a current limiting circuit, a transformer and a voltage conversion device; wherein:
the positive power supply end of the device input power supply is connected with the first end of the primary coil in the transformer, the negative power supply end of the device input power supply is connected with the first end of the current limiting circuit, the second end of the current limiting circuit is connected with the second end of the primary coil, the first end of the secondary coil in the transformer is connected with the first end of the voltage conversion device, the second end of the secondary coil and the second end of the voltage conversion device are both grounded, and two ends of the voltage conversion device are used as the output ends of the voltage mutual inductance circuit;
the voltage conversion device is used for converting a current signal flowing through the secondary coil into a voltage signal and supplying the voltage signal to the signal amplification circuit.
Preferably, the signal amplification circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor and a signal amplifier; wherein:
the first end of the first resistor is connected with the first end of the voltage conversion device, the second end of the first resistor is respectively connected with the first end of the second resistor, the first end of the first capacitor and the input positive end of the signal amplifier, the second end of the second resistor and the second end of the first capacitor are both grounded, the first end of the third resistor is connected with the second end of the voltage conversion device, the second end of the third resistor is respectively connected with the first end of the fourth resistor, the first end of the second capacitor and the input negative end of the signal amplifier, the second end of the fourth resistor is respectively connected with the second end of the second capacitor and the output end of the signal amplifier, and the common end of the fourth resistor is used as the output end of the signal amplification circuit.
Preferably, the peak detection circuit comprises a first operational amplifier, a second operational amplifier, a third capacitor, a fourth capacitor, a fifth resistor, a sixth resistor, a first diode and a second diode; wherein:
the positive input end of the first operational amplifier is connected with the output end of the signal amplification circuit, the negative input end of the first operational amplifier is respectively connected with the first end of the third capacitor, the anode of the first diode and the first end of the fifth resistor, the output end of the first operational amplifier is respectively connected with the second end of the third capacitor, the cathode of the first diode and the anode of the second diode, a second end of the fifth resistor is respectively connected with the negative input end of the second operational amplifier and the output end of the second operational amplifier, and a common end of the fifth resistor is used as the output end of the peak detection circuit, the cathode of the second diode is respectively connected with the first end of the fourth capacitor, the first end of the sixth resistor and the input positive end of the second operational amplifier, and the second end of the fourth capacitor and the second end of the sixth resistor are both grounded.
Preferably, the RC circuit comprises a fifth capacitor and a seventh resistor; wherein:
the first end of the seventh resistor is connected with the output end of the peak detection circuit, the second end of the seventh resistor is connected with the first end of the fifth capacitor, the common end of the seventh resistor is used as the output end of the voltage detection circuit, and the second end of the fifth capacitor is grounded.
Preferably, the control circuit includes:
the comparison circuit is connected with the output end of the voltage detection circuit and is used for comparing the power supply voltage with a preset overvoltage threshold value, and if the power supply voltage is greater than the preset overvoltage threshold value, a first level signal is output; otherwise, outputting a second level signal;
the switching circuit is connected with the output end of the comparison circuit and is used for cutting off a power supply line of an input power supply of the device after receiving the first level signal; and after receiving the second level signal, conducting the power supply line.
Preferably, the comparison circuit comprises a hysteresis comparator, an eighth resistor and a ninth resistor; wherein:
the first end of the eighth resistor is connected with the output end of the voltage detection circuit, the second end of the eighth resistor is connected with the positive input end of the hysteresis comparator and the first end of the ninth resistor respectively, the negative input end of the hysteresis comparator is connected with a voltage signal representing a preset overvoltage threshold, and the output end of the hysteresis comparator is connected with the second end of the ninth resistor and the public end of the hysteresis comparator serves as the output end of the comparison circuit.
Preferably, the switching circuit comprises a switching tube and a controllable switch arranged on a power supply line of the input power supply of the device; wherein:
the control end of the switch tube is connected with the output end of the comparison circuit, the first end of the switch tube is connected with the first end of the controllable switch, the second end of the switch tube is grounded, and the second end of the controllable switch is connected with a power supply; the comparison circuit is specifically used for controlling the switching tube to be conducted if the power supply voltage is larger than a preset overvoltage threshold value, so that the controllable switch is powered on and then the power supply line is cut off; otherwise, the switching tube is controlled to be switched off, so that the power supply line is switched on after the controllable switch is switched off.
Preferably, the switching circuit further includes a tenth resistor and an eleventh resistor; wherein:
the first end of the tenth resistor is connected with the output end of the comparison circuit, the second end of the tenth resistor is connected with the control end of the switch tube, the first end of the eleventh resistor is connected with the first end of the switch tube, and the second end of the eleventh resistor is connected with the first end of the controllable switch.
In order to solve the technical problem, the utility model also provides an overvoltage protection device, including input power supply and any kind of overvoltage protection circuit of the aforesaid.
The utility model provides an overvoltage crowbar, including voltage detection circuit and control circuit. The voltage detection circuit is used for detecting the power supply voltage of the input power supply of the device; the control circuit is used for cutting off a power supply line of the input power supply of the device when the power supply voltage is larger than a preset overvoltage threshold value. Therefore, the power supply circuit of the device can be cut off when the power supply voltage of the input power supply of the device is larger, so that the rear end circuit of the device is prevented from being burnt, and the safety and the reliability of the device are improved.
The utility model also provides an overvoltage protector, the same beneficial effect has with above-mentioned overvoltage protection circuit.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required in the prior art and the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an overvoltage protection circuit provided by the present invention;
fig. 2 is a schematic diagram of a specific structure of an overvoltage protection circuit provided by the present invention.
Detailed Description
The core of the utility model is to provide an overvoltage protection circuit and device can cut off its power supply line when the supply voltage of device input power is great to prevent that device rear end circuit from being burnt, thereby improved the security and the reliability of device.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an overvoltage protection circuit according to the present invention.
The overvoltage protection circuit includes:
the voltage detection circuit 1 is connected with the power supply end of the device input power supply and is used for detecting the power supply voltage of the device input power supply;
and the control circuit 2 is connected with the output end of the voltage detection circuit 1 and is used for cutting off a power supply line of an input power supply of the device when the power supply voltage is greater than a preset overvoltage threshold value.
Specifically, the overvoltage protection circuit of this application includes voltage detection circuit 1 and control circuit 2, and its theory of operation is:
the voltage detection circuit 1 is connected with the power supply end of the device input power supply, and is used for detecting the power supply voltage of the device input power supply and sending the power supply voltage of the device input power supply to the control circuit 2. The control circuit 2 compares the power supply voltage with a preset overvoltage threshold value after receiving the power supply voltage of the input power supply of the device, if the power supply voltage is greater than the preset overvoltage threshold value, the power supply voltage of the input power supply of the device is considered to be overvoltage, a power supply line of the input power supply of the device is cut off, the input power supply of the device is stopped to supply power to the rear end circuit of the device, and therefore the effect of preventing the rear end circuit of the device from being burnt is achieved.
The utility model provides an overvoltage crowbar, including voltage detection circuit and control circuit. The voltage detection circuit is used for detecting the power supply voltage of the input power supply of the device; the control circuit is used for cutting off a power supply line of the input power supply of the device when the power supply voltage is larger than a preset overvoltage threshold value. Therefore, the power supply circuit of the device can be cut off when the power supply voltage of the input power supply of the device is larger, so that the rear end circuit of the device is prevented from being burnt, and the safety and the reliability of the device are improved.
On the basis of the above-described embodiment:
referring to fig. 2, fig. 2 is a schematic diagram of a specific structure of an overvoltage protection circuit according to the present invention.
As an alternative embodiment, the voltage detection circuit 1 includes:
the voltage mutual inductance circuit 100 is connected with the power supply end of the device input power supply and is used for carrying out voltage reduction processing on the power supply voltage of the device input power supply to obtain a voltage reduction signal;
the signal amplification circuit 101 is connected with the output end of the voltage mutual inductance circuit 100 and is used for carrying out signal amplification processing on the voltage reduction signal to obtain a voltage amplification signal;
a peak detection circuit 102 connected to an output terminal of the signal amplification circuit 101, for detecting a peak value of the voltage amplification signal to obtain a voltage peak signal;
and an RC circuit 103 connected to an output terminal of the peak detection circuit 102, for filtering and rectifying the voltage peak signal to obtain a voltage effective value, and supplying the voltage effective value to the control circuit 2.
Specifically, the voltage detection circuit 1 of the present application includes a voltage transformer circuit 100, a signal amplifier circuit 101, a peak detector circuit 102, and an RC circuit 103, and its operating principle is as follows:
the voltage transformer circuit 100 is connected to a power supply terminal of the device input power supply, and is configured to step down a power supply voltage of the device input power supply to obtain a step-down signal, and send the step-down signal to the signal amplification circuit 101. After receiving the reduced voltage signal, the signal amplification circuit 101 performs signal amplification processing on the reduced voltage signal to obtain a voltage amplification signal, and sends the voltage amplification signal to the peak detection circuit 102. The peak detection circuit 102 receives the voltage amplification signal, detects a peak value of the voltage amplification signal, obtains a voltage peak signal, and transmits the voltage peak signal to the RC circuit 103. After receiving the voltage peak signal, the RC circuit 103 performs filtering rectification on the voltage peak signal to obtain a voltage effective value, and sends the voltage effective value to the control circuit 2 for comparison.
As an alternative embodiment, the voltage transformer circuit 100 includes a current limiting circuit, a transformer T and a voltage converting device; wherein:
the positive power supply end of the input power supply of the device is connected with the first end of a primary coil in the transformer T, the negative power supply end of the input power supply of the device is connected with the first end of a current limiting circuit, the second end of the current limiting circuit is connected with the second end of the primary coil, the first end of a secondary coil in the transformer T is connected with the first end of a voltage conversion device, the second end of the secondary coil and the second end of the voltage conversion device are both grounded, and the two ends of the voltage conversion device are used as the output ends of the voltage mutual inductance circuit 100;
the voltage conversion device is used for converting a current signal flowing through the secondary coil into a voltage signal to be supplied to the signal amplification circuit 101.
Specifically, the voltage transformer circuit 100 of the present application includes a current limiting circuit, a transformer T and a voltage conversion device, and its operating principle is:
the alternating current supply voltage of the device input power supply is input to the transformer T after being limited by the current limiting circuit. The transformer T carries out voltage reduction processing on the alternating current supply voltage of the device input power supply so as to convert the alternating current supply voltage of the device input power supply into a weak voltage signal; the transformer T induces the current flowing into the primary coil to the secondary coil according to the ratio of 1: 1; the transformer T also serves an electrical isolation in the circuit. The voltage conversion device converts a current signal flowing through the secondary coil of the transformer T into a voltage signal, and supplies the voltage signal to the signal amplification circuit 101 for processing.
More specifically, the current limiting circuit of the present application may be composed of a plurality of current limiting resistors connected in series, such as the resistor R84, the resistor R88, and the resistor R90 shown in fig. 2. The voltage conversion device of the present application may be implemented by a resistor, such as the resistor R95 shown in fig. 2. In addition, the voltage transformer circuit 100 of the present application may further include a capacitor C54 for filtering and stabilizing voltage.
As an alternative embodiment, the signal amplifying circuit 101 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, and a signal amplifier a 11; wherein:
a first end of the first resistor R1 is connected to a first end of the voltage conversion device, a second end of the first resistor R1 is connected to a first end of the second resistor R2, a first end of the first capacitor C1 and an input positive end of the signal amplifier a11, a second end of the second resistor R2 and a second end of the first capacitor C1 are both grounded, a first end of the third resistor R3 is connected to a second end of the voltage conversion device, a second end of the third resistor R3 is connected to a first end of the fourth resistor R4, a first end of the second capacitor C2 and an input negative end of the signal amplifier a11, a second end of the fourth resistor R4 is connected to a second end of the second capacitor C2 and an output end of the signal amplifier a11, and a common end is used as an output end of the signal amplification circuit 101.
Specifically, the signal amplification circuit 101 of the present application includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, and a signal amplifier a11, and its operating principle is:
the signal amplification circuit 101 of the present application performs signal amplification using a signal amplifier a11, in which,
the resistance of the second resistor R2 is equal to the resistance of the fourth resistor R4, and the resistance of the first resistor R1 is equal to the resistance of the third resistor R3, so that the signal amplification factor of the signal amplifier a11 is equal to the second resistor R2/the first resistor R1; the first capacitor C1 and the second capacitor C2 play a role of ensuring that an alternating current signal stably passes through.
As an alternative embodiment, the peak detector circuit 102 includes a first operational amplifier a21, a second operational amplifier a22, a third capacitor C3, a fourth capacitor C4, a fifth resistor R5, a sixth resistor R6, a first diode D1, and a second diode D2; wherein:
an input positive terminal of the first operational amplifier a21 is connected to an output terminal of the signal amplifying circuit 101, an input negative terminal of the first operational amplifier a21 is connected to a first terminal of the third capacitor C3, an anode of the first diode D1, and a first terminal of the fifth resistor R5, respectively, an output terminal of the first operational amplifier a21 is connected to a second terminal of the third capacitor C3, a cathode of the first diode D1, and an anode of the second diode D2, respectively, a second terminal of the fifth resistor R5 is connected to an input negative terminal of the second operational amplifier a22 and an output terminal of the second operational amplifier a22, respectively, and a common terminal thereof is used as an output terminal of the peak detector circuit 102, a cathode of the second diode D2 is connected to a first terminal of the fourth capacitor C4, a first terminal of the sixth resistor R6, and an input positive terminal of the second operational amplifier a22, respectively, and a second terminal of the fourth capacitor C4 and a second terminal of the sixth resistor R6 are grounded.
Specifically, the signal amplification circuit 101 of the present application outputs a sinusoidal signal, and the peak detection circuit 102 is configured to detect a peak value of the sinusoidal signal output from the signal amplification circuit 101 and supply the detected peak value to the RC circuit 103. It should be noted that the peak detection circuit 102 is configured to reduce the RC value of the RC circuit 103, thereby reducing the response delay time.
As an alternative embodiment, the RC circuit 103 includes a fifth capacitor C5 and a seventh resistor R7; wherein:
a first terminal of the seventh resistor R7 is connected to the output terminal of the peak detector circuit 102, a second terminal of the seventh resistor R7 is connected to a first terminal of the fifth capacitor C5, a common terminal is used as the output terminal of the voltage detector circuit 1, and a second terminal of the fifth capacitor C5 is grounded.
Specifically, the RC circuit 103 of the present application performs filtering rectification on the voltage peak signal to obtain a voltage effective value, and supplies the voltage effective value to the control circuit 2.
As an alternative embodiment, the control circuit 2 comprises:
the comparison circuit 104 is connected to the output end of the voltage detection circuit 1, and is configured to compare the power supply voltage with a preset overvoltage threshold, and output a first level signal if the power supply voltage is greater than the preset overvoltage threshold; otherwise, outputting a second level signal;
the switch circuit 105 is connected with the output end of the comparison circuit 104 and is used for cutting off a power supply line of the input power supply of the device after receiving the first level signal; and after receiving the second level signal, turning on the power supply line.
Specifically, the control circuit 2 of the present application includes a comparison circuit 104 and a switch circuit 105, and the operation principle thereof is as follows:
the comparison circuit 104 is connected to the output end of the voltage detection circuit 1, and configured to compare the power supply voltage output by the voltage detection circuit 1 with a preset overvoltage threshold, and output a first level signal to the switch circuit 105 if the power supply voltage is greater than the preset overvoltage threshold; if the power supply voltage is not greater than the predetermined over-voltage threshold, a second level signal is output to the switch circuit 105.
After receiving the first level signal, the switch circuit 105 cuts off a power supply line of the device input power supply to stop the device input power supply from supplying power to the device back end circuit, thereby playing a role in preventing the device back end circuit from being burnt; after receiving the second level signal, the switch circuit 105 turns on a power supply line of the device input power supply to ensure that the device input power supply normally supplies power to the device back-end circuit when the power supply of the device input power supply is not overvoltage.
As an alternative embodiment, the comparison circuit 104 includes a hysteresis comparator a3, an eighth resistor R8, and a ninth resistor R9; wherein:
a first end of the eighth resistor R8 is connected to an output end of the voltage detection circuit 1, a second end of the eighth resistor R8 is connected to an input positive terminal of the hysteresis comparator A3 and a first end of the ninth resistor R9, respectively, an input negative terminal of the hysteresis comparator A3 is connected to a voltage signal representing a preset overvoltage threshold, an output end of the hysteresis comparator A3 is connected to a second end of the ninth resistor R9, and a common end of the output end of the hysteresis comparator A3 is used as an output end of the comparison circuit 104.
Specifically, the comparison circuit 104 of the present application includes a hysteresis comparator a3, an eighth resistor R8, and a ninth resistor R9, and its operation principle is:
in order to prevent the output of the comparator circuit 104 from changing frequently, the comparator circuit 104 of the present application uses the hysteresis comparator a3 to perform voltage comparison, that is, the comparator circuit 104 outputs the first level signal to the switch circuit 105 only when the supply voltage output by the voltage detection circuit 1 is > (preset over-voltage threshold + preset value); when the supply voltage output by the voltage detection circuit 1 is < (preset overvoltage threshold value — preset value), the second level signal is output to the switch circuit 105.
In addition, as shown in fig. 2, the voltage signal representing the preset over-voltage threshold value, which is connected to the negative input terminal of the hysteresis comparator a3, can be realized by dividing the voltage VCC by the resistor R87 and the resistor R89.
As an alternative embodiment, the switching circuit 105 includes a switching tube Q1 and a controllable switch Q2 provided on a power supply line of the input power supply of the device; wherein:
the control end of the switching tube Q1 is connected with the output end of the comparison circuit 104, the first end of the switching tube Q1 is connected with the first end of the controllable switch Q2, the second end of the switching tube Q1 is grounded, and the second end of the controllable switch Q2 is connected with a power supply;
the comparison circuit 104 is specifically configured to control the switching tube Q1 to be turned on if the power supply voltage is greater than a preset overvoltage threshold value, so that the controllable switch Q2 cuts off the power supply line after being powered on; otherwise, the switching tube Q1 is controlled to be turned off, so that the controllable switch Q2 turns on the power supply line after being powered off.
Specifically, the switching circuit 105 of the present application includes a switching tube Q1 and a controllable switch Q2, and the operating principle thereof is as follows:
the controllable switch Q2 of the present application is a normally closed switch, such as a normally closed relay, that is closed when de-energized and open when energized. The working principle is explained by taking the controllable switch Q2 as a normally closed relay as an example: the comparison circuit 104 compares the power supply voltage output by the voltage detection circuit 1 with a preset overvoltage threshold, and if the power supply voltage is greater than the preset overvoltage threshold, the switch tube Q1 is controlled to be switched on, the coil L of the normally closed relay is switched on, and the switch K arranged on the power supply line of the device input power supply in the normally closed relay is switched off so as to cut off the power supply line of the device input power supply; if the power supply voltage is not greater than the preset overvoltage threshold, the switch tube Q1 is controlled to be disconnected, the coil L of the normally closed relay is powered off, and the switch K arranged on the power supply line of the input power supply of the device in the normally closed relay is closed to conduct the power supply line of the input power supply of the device.
As an alternative embodiment, the switch circuit further includes a tenth resistor R10 and an eleventh resistor R11; wherein:
a first end of the tenth resistor R10 is connected to the output end of the comparator circuit 104, a second end of the tenth resistor R10 is connected to the control end of the switching transistor Q1, a first end of the eleventh resistor R11 is connected to the first end of the switching transistor Q1, and a second end of the eleventh resistor R11 is connected to the first end of the controllable switch Q2.
Further, the switch circuit 105 of the present application further includes a tenth resistor R10 and an eleventh resistor R11, the tenth resistor R10 plays a current limiting role, the eleventh resistor R11 plays a voltage dividing role, and both resistors are used for preventing the switch tube Q1 from being burnt, so that the circuit safety is improved.
The application also provides an overvoltage protection device which comprises an input power supply and any one of the overvoltage protection circuits.
For the introduction of the overvoltage protection device provided in the present application, reference is made to the above embodiments of the overvoltage protection circuit, and details of the overvoltage protection device are not repeated herein.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (11)
1. An overvoltage protection circuit, comprising:
the voltage detection circuit is connected with the power supply end of the device input power supply and is used for detecting the power supply voltage of the device input power supply;
and the control circuit is connected with the output end of the voltage detection circuit and is used for cutting off a power supply line of the input power supply of the device when the power supply voltage is greater than a preset overvoltage threshold value.
2. The overvoltage protection circuit of claim 1, wherein the voltage detection circuit comprises:
the voltage mutual inductance circuit is connected with the power supply end of the device input power supply and is used for carrying out voltage reduction processing on the power supply voltage of the device input power supply to obtain a voltage reduction signal;
the signal amplification circuit is connected with the output end of the voltage mutual inductance circuit and is used for carrying out signal amplification processing on the voltage reduction signal to obtain a voltage amplification signal;
the peak detection circuit is connected with the output end of the signal amplification circuit and is used for detecting the peak value of the voltage amplification signal to obtain a voltage peak value signal;
and the RC circuit is connected with the output end of the peak detection circuit and is used for filtering and rectifying the voltage peak signal to obtain a voltage effective value and supplying the voltage effective value to the control circuit.
3. The overvoltage protection circuit of claim 2, wherein said voltage transformer circuit includes a current limiting circuit, a transformer and a voltage conversion device; wherein:
the positive power supply end of the device input power supply is connected with the first end of the primary coil in the transformer, the negative power supply end of the device input power supply is connected with the first end of the current limiting circuit, the second end of the current limiting circuit is connected with the second end of the primary coil, the first end of the secondary coil in the transformer is connected with the first end of the voltage conversion device, the second end of the secondary coil and the second end of the voltage conversion device are both grounded, and two ends of the voltage conversion device are used as the output ends of the voltage mutual inductance circuit;
the voltage conversion device is used for converting a current signal flowing through the secondary coil into a voltage signal and supplying the voltage signal to the signal amplification circuit.
4. The overvoltage protection circuit of claim 3, wherein the signal amplification circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, and a signal amplifier; wherein:
the first end of the first resistor is connected with the first end of the voltage conversion device, the second end of the first resistor is respectively connected with the first end of the second resistor, the first end of the first capacitor and the input positive end of the signal amplifier, the second end of the second resistor and the second end of the first capacitor are both grounded, the first end of the third resistor is connected with the second end of the voltage conversion device, the second end of the third resistor is respectively connected with the first end of the fourth resistor, the first end of the second capacitor and the input negative end of the signal amplifier, the second end of the fourth resistor is respectively connected with the second end of the second capacitor and the output end of the signal amplifier, and the common end of the fourth resistor is used as the output end of the signal amplification circuit.
5. The overvoltage protection circuit of claim 2, wherein the peak detection circuit comprises a first operational amplifier, a second operational amplifier, a third capacitor, a fourth capacitor, a fifth resistor, a sixth resistor, a first diode, and a second diode; wherein:
the positive input end of the first operational amplifier is connected with the output end of the signal amplification circuit, the negative input end of the first operational amplifier is respectively connected with the first end of the third capacitor, the anode of the first diode and the first end of the fifth resistor, the output end of the first operational amplifier is respectively connected with the second end of the third capacitor, the cathode of the first diode and the anode of the second diode, a second end of the fifth resistor is respectively connected with the negative input end of the second operational amplifier and the output end of the second operational amplifier, and a common end of the fifth resistor is used as the output end of the peak detection circuit, the cathode of the second diode is respectively connected with the first end of the fourth capacitor, the first end of the sixth resistor and the input positive end of the second operational amplifier, and the second end of the fourth capacitor and the second end of the sixth resistor are both grounded.
6. The overvoltage protection circuit of claim 2, wherein the RC circuit includes a fifth capacitor and a seventh resistor; wherein:
the first end of the seventh resistor is connected with the output end of the peak detection circuit, the second end of the seventh resistor is connected with the first end of the fifth capacitor, the common end of the seventh resistor is used as the output end of the voltage detection circuit, and the second end of the fifth capacitor is grounded.
7. The overvoltage protection circuit of any one of claims 1-6, wherein the control circuit comprises:
the comparison circuit is connected with the output end of the voltage detection circuit and is used for comparing the power supply voltage with a preset overvoltage threshold value, and if the power supply voltage is greater than the preset overvoltage threshold value, a first level signal is output; otherwise, outputting a second level signal;
the switching circuit is connected with the output end of the comparison circuit and is used for cutting off a power supply line of an input power supply of the device after receiving the first level signal; and after receiving the second level signal, conducting the power supply line.
8. The overvoltage protection circuit of claim 7, wherein the comparison circuit includes a hysteresis comparator, an eighth resistor, and a ninth resistor; wherein:
the first end of the eighth resistor is connected with the output end of the voltage detection circuit, the second end of the eighth resistor is connected with the positive input end of the hysteresis comparator and the first end of the ninth resistor respectively, the negative input end of the hysteresis comparator is connected with a voltage signal representing a preset overvoltage threshold, and the output end of the hysteresis comparator is connected with the second end of the ninth resistor and the public end of the hysteresis comparator serves as the output end of the comparison circuit.
9. The overvoltage protection circuit of claim 7, wherein said switching circuit includes a switching tube and a controllable switch disposed in a supply line of said device input power; wherein:
the control end of the switch tube is connected with the output end of the comparison circuit, the first end of the switch tube is connected with the first end of the controllable switch, the second end of the switch tube is grounded, and the second end of the controllable switch is connected with a power supply;
the comparison circuit is specifically used for controlling the switching tube to be conducted if the power supply voltage is larger than a preset overvoltage threshold value, so that the controllable switch is powered on and then the power supply line is cut off; otherwise, the switching tube is controlled to be switched off, so that the power supply line is switched on after the controllable switch is switched off.
10. The overvoltage protection circuit of claim 9, wherein the switching circuit further includes tenth and eleventh resistors; wherein:
the first end of the tenth resistor is connected with the output end of the comparison circuit, the second end of the tenth resistor is connected with the control end of the switch tube, the first end of the eleventh resistor is connected with the first end of the switch tube, and the second end of the eleventh resistor is connected with the first end of the controllable switch.
11. An overvoltage protection device comprising an input power supply and an overvoltage protection circuit as claimed in any one of claims 1 to 10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120157628.8U CN214153994U (en) | 2021-01-20 | 2021-01-20 | Overvoltage protection circuit and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120157628.8U CN214153994U (en) | 2021-01-20 | 2021-01-20 | Overvoltage protection circuit and device |
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| Publication Number | Publication Date |
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| CN214153994U true CN214153994U (en) | 2021-09-07 |
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|---|---|---|---|
| CN202120157628.8U Active CN214153994U (en) | 2021-01-20 | 2021-01-20 | Overvoltage protection circuit and device |
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| CN (1) | CN214153994U (en) |
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- 2021-01-20 CN CN202120157628.8U patent/CN214153994U/en active Active
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Address after: No. 957, Shunda Road, Gaoxin District, Changchun City, Jilin Province, 130000 Patentee after: Changchun Jieyi Automobile Technology Co.,Ltd. Address before: Floor 1, 957 Shunda Road, Changchun hi tech Development Zone, Jilin Province 130000 Patentee before: CHANGCHUN JIEYI AUTO PARTS CO.,LTD. |
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