CN214626335U - Input voltage overvoltage protection circuit - Google Patents
Input voltage overvoltage protection circuit Download PDFInfo
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- CN214626335U CN214626335U CN202120605141.1U CN202120605141U CN214626335U CN 214626335 U CN214626335 U CN 214626335U CN 202120605141 U CN202120605141 U CN 202120605141U CN 214626335 U CN214626335 U CN 214626335U
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Abstract
The application relates to overvoltage protection's technical field especially relates to an input voltage overvoltage crowbar, including load power VCC and power supply circuit, still include: the rectifying circuit is connected with the power supply circuit and used for converting the initial voltage of the alternating current into the working voltage of the direct current; the voltage stabilizing circuit is connected with the rectifying circuit and used for stabilizing and outputting the working voltage; the voltage comparison circuit is connected with the voltage stabilizing circuit, compares the working voltage output by the voltage stabilizing circuit with two preset reference values respectively and outputs a first judgment signal and a second judgment signal respectively; the voltage judging circuit is connected with the voltage comparing circuit and used for receiving the first judging signal and the second judging signal and outputting an executing signal after processing; and the execution circuit is connected to the output end of the voltage judgment circuit and receives the execution signal and is used for controlling the electric appliance to be started or closed. The application has the effect of improving the defect that the electric appliance is not convenient to protect.
Description
Technical Field
The application relates to the technical field of overvoltage protection, in particular to an input voltage overvoltage protection circuit.
Background
With the development of science and technology, electronic devices including computers, tablet computers, mobile terminals and the like have increasingly close relationship with the work and life of people, and the electronic devices cannot be powered and protected by reliable power supplies.
In the prior art, when an electrical appliance operates, a power supply voltage within a certain range needs to be used for driving. When the supply voltage value can not reach this scope, easily lead to using electrical apparatus two kinds of condition to take place, one kind is because input voltage is too high, surpasss to bear the voltage with electrical apparatus and leads to using electrical apparatus to damage, another kind is because input voltage is too low, can't satisfy with electrical apparatus service voltage for it is low to use electrical apparatus work efficiency.
With respect to the related art in the above, the inventor believes that there is a drawback that it is inconvenient to protect the electrical appliance when the circuit voltage does not meet the electrical appliance power supply requirement.
SUMMERY OF THE UTILITY MODEL
In order to improve the defect that the protection of the electric appliance is inconvenient, the application provides an input voltage overvoltage protection circuit, which adopts the following technical scheme:
an input voltage overvoltage protection circuit, includes load power VCC and power supply circuit, still includes:
the rectifying circuit is connected with the power supply circuit and used for converting the initial voltage of the alternating current into the working voltage of the direct current;
the voltage stabilizing circuit is connected with the rectifying circuit and used for stabilizing and outputting the working voltage;
the voltage comparison circuit is connected with the voltage stabilizing circuit, compares the working voltage output by the voltage stabilizing circuit with two preset reference values respectively and outputs a first judgment signal and a second judgment signal respectively;
the voltage judging circuit is connected with the voltage comparing circuit and used for receiving the first judging signal and the second judging signal and outputting an executing signal after processing;
and the execution circuit is connected to the output end of the voltage judgment circuit and receives the execution signal and is used for controlling the electric appliance to be started or closed.
By adopting the technical scheme, when the electrical appliance is protected, alternating current is firstly converted into direct current through the rectifying circuit, then the voltage stabilizing circuit carries out voltage stabilizing operation on the converted direct current, then the voltage comparison circuit detects the stabilized voltage, detected detection signals are transmitted to the voltage judgment circuit through the circuit, the voltage judgment circuit judges the detection signals, the judged judgment signals are transmitted to the execution circuit, and finally the execution circuit executes operation on the switch of the electrical appliance according to the judgment signals, so that the effect of improving the defect that the electrical appliance is not convenient to protect is achieved.
Optionally, the power circuit includes a transformer T, a primary side coil of the transformer T is connected to the utility power, a secondary side coil of the transformer T is connected to the rectifier circuit, the rectifier circuit is a bridge rectifier circuit, and an ac input end of the bridge rectifier circuit is connected to the secondary side coil of the transformer T.
By adopting the technical scheme, when alternating current is converted into direct current, the transformer T converts commercial voltage into household voltage, then the bridge rectifier current converts the converted alternating voltage into direct current voltage, the bridge rectifier circuit is high in integration level, and a connection circuit is convenient and simple; meanwhile, the bridge rectifier circuit has good rectification effect and can improve the rectification effect.
Optionally, the voltage stabilizing circuit includes a voltage stabilizing chip and a potentiometer, an input end of the voltage stabilizing chip is connected to an anode output end of the bridge rectifier circuit, an adjusting end of the voltage stabilizing chip is connected to one fixed end of the potentiometer RP, the other fixed end of the potentiometer RP is grounded, and an adjusting end of the potentiometer RP is grounded.
Through adopting above-mentioned technical scheme, DC voltage flows through voltage stabilizing chip, and voltage stabilizing chip stabilizes the DC voltage frequency, and potentiometre RP adjusts voltage stabilizing chip's output for rectifier chip can output different operating voltage with the electrical apparatus of the different demands of adaptation, has promoted suitability and convenience.
Optionally, the voltage comparison circuit includes a voltage comparator chip, and the voltage comparison chip is a model LM393 chip.
By adopting the technical scheme, the voltage comparator chip is a model LM393 chip, two independent voltage comparators are arranged in the LM393 chip, reference values of zero-crossing voltage and overvoltage voltage are preset for ref ends of the two voltage comparators respectively, then the stabilized direct current voltage is compared with the reference value, and a high level is output when the direct current voltage is greater than the reference value; when the direct current voltage is smaller than the reference value, the low level is output, so that the effect of detecting whether the voltage meets the use voltage of the electric appliance is achieved.
Optionally, the voltage determining circuit includes an NPN triode and an xor gate, two input ends of the xor gate are respectively connected to two output ends of the voltage comparing circuit to receive the first determining signal and the second determining signal, a base of the NPN triode is connected to an output end of the xor gate, an emitter of the NPN triode is connected to the executing circuit, and a collector of the NPN triode is connected to the load power VCC.
By adopting the technical scheme, the principle of the exclusive-OR gate is that if the levels of the two input ends are different, a high level is output; if the levels of the two input ends of the exclusive-OR gate are the same, a low level is output, so that after the input end of the exclusive-OR gate receives a level signal processed by the voltage comparator chip, whether the level meets the conduction requirement is judged according to the conduction distance of the exclusive-OR gate, and the effect of judging the direct-current voltage is achieved.
Optionally, the execution circuit includes an electromagnetic relay KM, one end of a coil of the electromagnetic relay KM is connected to an emitter of the NPN triode, and the other end of the coil of the electromagnetic relay KM is grounded; one end of a normally open contact KM-1 of the electromagnetic relay KM is connected to the output end of the voltage stabilizing circuit, the other end of the normally open contact KM-1 is connected to the power supply anode of the electric appliance, and the power supply cathode of the electric appliance is grounded.
By adopting the technical scheme, when the NPN triode is conducted, the coil of the electromagnetic relay KM is electrified, the normally open contact KM-1 of the electromagnetic relay KM is closed, and the electric appliance works normally; when the NPN triode is not conducted, the coil of the electromagnetic relay KM loses power, and the normally open contact KM-1 of the electromagnetic relay KM is kept disconnected, so that the effect of protecting an electric appliance is achieved.
Optionally, the voltage stabilizing chip is connected with a resistor R, one end of the resistor R is connected to the input end of the voltage stabilizing chip, the other end of the resistor R is connected in series with a capacitor C, and the other end of the capacitor C is grounded.
By adopting the technical scheme, when the capacitor C is used, the resistor R has the function of voltage division, the situation that the capacitor C is broken down is reduced, and the effect of protecting the capacitor C is achieved; the capacitor C filters the direct current voltage, and the effect of stable direct current voltage output is achieved.
Optionally, two ends of the electrical appliance are connected in parallel with a voltmeter V.
Through adopting above-mentioned technical scheme, voltmeter V can detect the voltage and the demonstration with electrical apparatus during operation, and the staff of being convenient for observes the operating condition of circuit, promotes the convenience of regulating voltage.
In summary, the present application includes at least one of the following beneficial technical effects:
1. by arranging the protection circuit device, when the voltage is greater than or less than the service voltage of the electric appliance, the normally open contact KM-1 of the electromagnetic relay KM is kept disconnected, and the electric appliance does not work, so that the defect that the circuit voltage is inconvenient to detect is overcome;
2. through setting up voltmeter V device for operating personnel carries out real-time supervision to the voltage in the circuit, has reached the effect that improves mediation voltage convenience.
Drawings
Fig. 1 is an overall circuit schematic diagram of an input voltage overvoltage protection circuit according to an embodiment of the present application.
Description of reference numerals: 1. a power supply circuit; 2. an electrical appliance; 3. a rectifying circuit; 4. a voltage stabilizing circuit; 41. a voltage stabilization chip; 5. a voltage comparison circuit; 51. a voltage comparator chip; 6. a voltage judging circuit; 7. an execution circuit.
Detailed Description
The present application is described in further detail below with reference to fig. 1.
The embodiment of the application discloses an input voltage overvoltage protection circuit. Referring to fig. 1, the power supply circuit 1 includes a power supply circuit 1, a rectification circuit 3, a voltage stabilizing circuit 4, a voltage comparison circuit 5, a voltage judgment circuit 6, an execution circuit 7, a load power supply VCC and an electric appliance 2, and the power supply circuit 1 outputs an initial voltage after stepping down a commercial power; after receiving the initial voltage, the rectifying circuit 3 converts alternating current into direct current; the voltage stabilizing circuit 4 stabilizes the converted direct-current voltage and transmits the stabilized direct-current voltage to the voltage comparison circuit 5, and the voltage comparison circuit 5 compares the direct-current voltage with a preset reference value and respectively outputs a first judgment signal and a second judgment signal; the voltage judging circuit 6 is connected to the output end of the voltage comparing circuit 5 and receives the first judging signal and the second judging signal, and outputs an executing signal after processing; the load power VCC is connected to the input end of the execution circuit 7, and provides voltage for the execution circuit 7, and the execution circuit 7 is connected to the output end of the voltage judgment circuit 6 and receives the execution signal, and is used for controlling the start or the close of the electrical appliance 2, so that the effect of improving the defect that the electrical appliance is not convenient to protect is achieved.
Referring to fig. 1, the power supply circuit 1 includes a transformer T, the rectifier circuit 3 is a bridge rectifier circuit, an ac input end of the bridge rectifier circuit is connected to a secondary side coil of the transformer T, and a negative output end of the bridge rectifier circuit is grounded. When alternating current is converted into direct current, the transformer T converts commercial voltage into household voltage, then bridge rectifier current converts the converted alternating voltage into direct current voltage, the integration level of a bridge rectifier circuit is high, and a connection circuit is convenient and simple; meanwhile, the bridge rectifier circuit has good rectification effect and can improve the rectification effect.
Referring to fig. 1, the voltage stabilizing circuit 4 includes a voltage stabilizing chip 41 and a potentiometer RP, the voltage stabilizing chip 41 is a model LM317 chip, an input end of the LM317 chip is connected to an anode output end of the bridge rectifier circuit 3, an adjusting end of the LM317 chip is connected to a fixed end of the potentiometer RP, and another fixed end and the adjusting end of the potentiometer RP are grounded. When direct current voltage flows through voltage stabilization chip 41, voltage stabilization chip 41 stabilizes direct current voltage frequency, and potentiometre RP adjusts voltage stabilization chip 41's output for rectifier chip can output different operating voltage with the different demands of adaptation with electrical apparatus 2, has reached the effect that has promoted suitability and convenience.
Referring to fig. 1, the voltage comparison circuit 5 includes a voltage comparator chip 51, the voltage comparator chip 51 is an LM393 chip, two independent voltage comparators are disposed in the LM393 chip, an input terminal pin 2 and a pin 6 of the voltage comparator chip 51 are respectively connected to an output terminal of the LM317 chip, a pin 3 of the voltage comparator chip 51 is preset with a zero-crossing voltage value, a pin 5 of the voltage comparator chip 51 is preset with an overvoltage voltage value, an output pin 1 and a pin 7 of the voltage comparator chip 51 are connected to an input terminal of the judgment circuit 6 after being xored, a pin 4 of the voltage comparator chip 51 is grounded, and a pin 8 of the voltage comparator chip 51 is connected to a power supply load VCC. Then comparing the stabilized direct current voltage with a zero-crossing voltage value and an overvoltage voltage value, and outputting a high level when the direct current voltage is greater than the zero-crossing voltage value, otherwise outputting a low level; and when the direct current voltage is greater than the overvoltage voltage value, outputting a high level, otherwise, outputting a low level.
Referring to fig. 1, the voltage judging circuit 6 includes an exclusive or gate and an NPN triode, two input terminals of the exclusive or gate are respectively connected to output terminals of two voltage comparators in the LM393 chip, a base of the NPN triode is connected to an output terminal of the exclusive or gate, an emitter of the NPN triode is connected to the executing circuit 7, and a collector of the NPN triode is connected to the load power VCC. The principle of the exclusive-OR gate is that if the levels of the two input ends are different, a high level is output; if the two input ends of the exclusive-OR gate have the same level, a low level is output. Therefore, after the input end of the exclusive-OR gate receives the level signal processed by the voltage comparator chip, whether the level meets the conduction requirement is judged according to the conduction distance of the exclusive-OR gate, and therefore the direct-current voltage is judged.
Referring to fig. 1, the execution circuit 7 includes an electromagnetic relay KM, one end of a coil of the electromagnetic relay KM is connected to an emitter of the NPN transistor, and the other end is grounded; one end of a normally open contact KM-1 of the electromagnetic relay KM is connected with the output end of the voltage stabilizing circuit 2, the other end of the normally open contact KM-1 is connected with the power supply anode of the electrical appliance 2, the power supply cathode of the electrical appliance 2 is grounded, and the two ends of the anode and the cathode of the electrical appliance 2 are connected in parallel with a voltmeter V. When the output end of the exclusive-OR gate outputs a high level, the NPN triode is conducted, a coil of the electromagnetic relay KM is electrified, a normally open contact KM-1 of the electromagnetic relay KM is closed, and the electrical appliance 2 works normally; when the output end of the exclusive-OR gate outputs a low-level execution signal, the NPN triode is not conducted, the coil of the electromagnetic relay KM loses power, the normally open contact KM-1 of the electromagnetic relay KM keeps disconnected, and meanwhile, the voltmeter V detects the voltage of the electrical appliance 2, so that a worker can conveniently check the working condition of the circuit, and the effect of protecting the electrical appliance 2 is achieved.
Referring to fig. 1, a resistor R is connected to the voltage stabilization chip 41, one end of the resistor R is connected to an input end of the voltage stabilization chip 41, the other end of the resistor R is connected in series with a capacitor C, and one end of the capacitor C, which is not connected to the resistor R, is grounded. When the voltage divider is used, the capacitor C has a filtering effect on the direct-current voltage, the direct-current voltage is more stable to output, the resistor R has a voltage dividing effect on the capacitor C, and the capacitor C is not prone to breakdown.
The implementation principle of an input voltage overvoltage protection circuit in the embodiment of the application is as follows: the power circuit 1 outputs initial voltage after reducing the voltage of the commercial power, and the bridge rectifier circuit 3 converts alternating current into direct current after receiving the initial voltage; the LM317 chip stabilizes the direct current voltage after conversion, and conveys the direct current voltage after stabilizing to the LM393 chip, the LM393 chip detects the direct current voltage and uses the interval, and convey the signal of telecommunication after detecting to the exclusive-OR gate, the exclusive-OR gate conveys different signal of telecommunication according to different signal of telecommunication, transmit the signal of telecommunication to the NPN triode, the NPN triode receives the signal of telecommunication after, judges different signals of telecommunication, and then control detects with electrical apparatus 2 on-off state, voltmeter V to circuit voltage.
The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.
Claims (8)
1. An input voltage overvoltage protection circuit, characterized by: including load power VCC and power supply circuit (1), still include:
a rectifying circuit (3) connected to the power supply circuit (1) for converting an initial voltage of the alternating current into a working voltage of the direct current;
the voltage stabilizing circuit (4) is connected to the rectifying circuit (3) and used for stabilizing and outputting the working voltage;
the voltage comparison circuit (5) is connected to the voltage stabilizing circuit (4), compares the working voltage output by the voltage stabilizing circuit with two preset reference values respectively, and outputs a first judgment signal and a second judgment signal respectively;
the voltage judging circuit (6) is connected with the voltage comparing circuit (5) and is used for receiving the first judging signal and the second judging signal and outputting an executing signal after processing;
and the execution circuit (7) is connected to the output end of the voltage judgment circuit (6) and receives the execution signal, and is used for controlling the electrical appliance (2) to be started or closed.
2. An input voltage overvoltage protection circuit according to claim 1, wherein: the power supply circuit (1) comprises a transformer T, a primary side coil of the transformer T is connected to a mains supply, a secondary side coil of the transformer T is connected to a rectification circuit (3), the rectification circuit (3) is a bridge rectification circuit, and an alternating current input end of the bridge rectification circuit is connected with the secondary side coil of the transformer T.
3. An input voltage overvoltage protection circuit according to claim 2, wherein: the voltage stabilizing circuit (4) comprises a voltage stabilizing chip (41) and a potentiometer RP, the input end of the voltage stabilizing chip (41) is connected to the positive electrode output end of the bridge rectifier circuit (3), the adjusting end of the voltage stabilizing chip (41) is connected to one fixed end of the potentiometer RP, the other fixed end of the potentiometer RP is grounded, and the adjusting end of the potentiometer RP is grounded.
4. An input voltage overvoltage protection circuit according to claim 3, wherein: the voltage comparison circuit (5) comprises a voltage comparator chip (51), and the voltage comparator chip (51) is a model LM393 chip.
5. An input voltage overvoltage protection circuit according to claim 4, wherein: the voltage judging circuit (6) comprises an NPN triode and an exclusive-OR gate, two input ends of the exclusive-OR gate are respectively connected with two output ends of the voltage comparing circuit (5) to receive the first judging signal and the second judging signal, a base electrode of the NPN triode is connected with the output end of the exclusive-OR gate, an emitting electrode of the NPN triode is connected with the executive circuit (7), and a collecting electrode of the NPN triode is connected with a load power supply VCC.
6. An input voltage overvoltage protection circuit according to claim 5, wherein: the execution circuit (7) comprises an electromagnetic relay KM, one end of a coil of the electromagnetic relay KM is connected to an emitting electrode of the NPN triode, and the other end of the coil of the electromagnetic relay KM is grounded; one end of a normally open contact KM-1 of the electromagnetic relay KM is connected to the output end of the voltage stabilizing circuit (4), the other end of the normally open contact KM-1 is connected to the power supply anode of the electrical appliance (2), and the power supply cathode of the electrical appliance (2) is grounded.
7. An input voltage overvoltage protection circuit according to claim 3, wherein: the voltage stabilizing chip (41) is connected with a resistor R, one end of the resistor R is connected to the input end of the voltage stabilizing chip (41), the other end of the resistor R is connected with a capacitor C in series, and the other end of the capacitor C is grounded.
8. An input voltage overvoltage protection circuit according to claim 1, wherein: and two ends of the electric appliance (2) are connected with a voltmeter V in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120605141.1U CN214626335U (en) | 2021-03-25 | 2021-03-25 | Input voltage overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120605141.1U CN214626335U (en) | 2021-03-25 | 2021-03-25 | Input voltage overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214626335U true CN214626335U (en) | 2021-11-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120605141.1U Active CN214626335U (en) | 2021-03-25 | 2021-03-25 | Input voltage overvoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214626335U (en) |
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2021
- 2021-03-25 CN CN202120605141.1U patent/CN214626335U/en active Active
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