CN209056921U - A kind of DC power supply overvoltage crowbar - Google Patents

Abstract

The utility model provides a kind of DC power supply overvoltage crowbar, including first capacitor, second capacitor, first resistor, second resistance, first diode, second diode, triode, field-effect tube, first capacitor and the second capacitor are filtering part, effectively filter out the high and low frequency signal in circuit, first resistor, second resistance, first diode, second diode, triode and field-effect tube form protection circuit, when there are when larger voltage peak for power supply, base stage by the second diode of breakdown in triode accesses positive voltage, so that the collector and emitter of triode is connected, the grid bias of further field-effect tube reduces, the drain electrode of field-effect tube and source electrode cut-off, so that power input negative terminal and power input positive terminal disconnect, it is effectively protected next stage application circuit, the utility model structure Simply, device is easily purchased, and is had a wide range of application.

Description

A kind of DC power supply overvoltage crowbar

Technical field

The utility model relates to power supply overvoltage protection technical field more particularly to a kind of DC power supply overvoltage crowbars.

Background technique

With the rapid development of electronic technology, electronic product is more and more, has much DC power supply is needed to power in the market Product, such as smart machine, LED illumination, charger, integrated chip etc..Since there are voltage is dry for the input terminal of such product It disturbs or crosstalk, causes supply voltage unstable, it, can be to the entire application in product if there is the peak value of excessive input voltage Circuit interferes, and may cause application circuit and does not work or seriously burn.In electrical equipment operational process, if playing key The processing chip of effect is damaged, and undoubtedly will lead to the paralysis of entire circuit system.Existing power supply includes that power input is rectified Extremely sub- P+, power input negative terminal P-, power output end positive terminal Vbus+, power output end negative terminal Vbus-, power input positive terminal P+ are connect with power output end positive terminal Vbus+, power input negative terminal P- It is connect with power output end negative terminal Vbus-.Existing overvoltage protection scheme mostly uses greatly dedicated overvoltage protection IC, but device Part is not easy to purchase, and dedicated overvoltage protection IC is at high cost, is not easy to promote and apply.

Summary of the invention

The utility model aim is to provide a kind of DC power supply overvoltage crowbar, can effectively avoid supply voltage peak To the damage of application circuit when being worth excessively high, and structure is simple, easy to promote and utilize.

The utility model use the specific scheme is that

The utility model includes first capacitor, the second capacitor, first resistor, second resistance, first diode, the two or two pole Pipe, triode, field-effect tube, the power input positive terminal P+ is connect with power output end positive terminal Vbus+, described The first end of first capacitor is connect with power input positive terminal P+, and the second end and power input of the first capacitor are negative Extremely sub- P- connection, the first end of second capacitor are connect with power input positive terminal P+, and the of second capacitor Two ends are connect with power input negative terminal P-, and the first end and power input positive terminal P+ of the second resistance connect It connects, the second end of the second resistance is connect with the cathode of the second diode, the anode of second diode and three pole The base stage of pipe connects, and the emitter-base bandgap grading of the triode is connect with the power input negative terminal P-, the current collection of the triode The connection of the first end of pole and first resistor, the second end of the first resistor are connect with power output end positive terminal Vbus+, institute The first end of the cathode and first resistor of stating first diode connects, the anode and power input cathode of the first diode Terminals P-connection, the grid of the field-effect tube and the first end of first resistor connect, the source electrode and power supply of the field-effect tube The drain electrode of input cathode terminals P-connection, the field-effect tube is connect with power output end negative terminal Vbus-.

Preferably, the first resistor, second resistance are metalfilmresistor.

For low frequency signal present in filtering circuit, the first capacitor is electrolytic capacitor.

Further, for the high-frequency signal in filtering circuit, second capacitor is ceramic condenser.

Preferably, the field-effect tube is N-channel field-effect tube.

The utility model can effectively avoid DC power supply from damaging when exporting biggish crest voltage to application circuit, And structure is simple, and device is easy to purchase, and has a wide range of application.

Detailed description of the invention

Fig. 1 is the circuit diagram of the utility model.

Specific embodiment

The utility model is illustrated with reference to the accompanying drawing

The utility model includes first capacitor, the second capacitor, first resistor, second resistance, first diode, the two or two pole Pipe, triode, field-effect tube, the power input positive terminal P+ is connect with power output end positive terminal Vbus+, described The first end of first capacitor is connect with power input positive terminal P+, and the second end and power input of the first capacitor are negative Extremely sub- P- connection, the first end of second capacitor are connect with power input positive terminal P+, and the of second capacitor Two ends are connect with power input negative terminal P-, and the first end and power input positive terminal P+ of the second resistance connect It connects, the second end of the second resistance is connect with the cathode of the second diode, the anode of second diode and three pole The base stage of pipe connects, and the emitter-base bandgap grading of the triode is connect with the power input negative terminal P-, the current collection of the triode The connection of the first end of pole and first resistor, the second end of the first resistor are connect with power output end positive terminal Vbus+, institute The first end of the cathode and first resistor of stating first diode connects, the anode and power input cathode of the first diode Terminals P-connection, the grid of the field-effect tube and the first end of first resistor connect, the source electrode and power supply of the field-effect tube The drain electrode of input cathode terminals P-connection, the field-effect tube is connect with power output end negative terminal Vbus-.

By taking direct current 12V supply voltage protects circuit as an example, the first resistor R1, second resistance R2 are metal film electricity Resistance, precision 0.5%, specifically, the first resistor R1 resistance value are 100K ohm, and the second resistance R2 resistance value is 1K ohm.

For low frequency signal present in filtering circuit, the first capacitor C1 is electrolytic capacitor, specifically, described first Capacitor C1 is 220 microfarads, the alminium electrolytic condenser that precision is 5%.

Further, for the high-frequency signal in filtering circuit, the second capacitor C2 is ceramic condenser, specifically, institute Stating the second capacitor C2 is 104.

Preferably, the field-effect tube IC1 is N-channel field-effect tube, and NCE6080K specifically can be used.

Specifically, the triode Q1 model MMBT5551.

The first diode ZW1, the second diode ZW2 are all made of ZMM12V.

When power input accesses 12V DC power supply, first capacitor C1 and the second capacitor C2 are filtering part, first Low frequency signal in capacitor C1 filtering circuit, the second capacitor C2 filtering circuit high frequency signal guarantee 12V DC power good. 12V DC power supply passes through the grid of first resistor R1 connection field-effect tube IC1 simultaneously, and the grid for being field-effect tube IC1 is powered.When When input terminal voltage is stablized, first diode ZW1 is in off state, is formed between the grid and source electrode of field-effect tube IC1 inclined Set voltage, the drain electrode of field-effect tube IC1 and source conduction, power input negative terminal P- and power output end negative terminal Vbus- conducting, 12V DC power supply are application circuit power supply.

When input terminal due to voltage disturbance or crosstalk there are when excessive input voltage peak value, power input positive terminal P+ forms biggish voltage difference at the second both ends diode ZW2 by second resistance R2, and the second diode ZW2 is breakdown, this When triode Q1 base stage access positive voltage, the collector and emitter conducting of triode Q1, the grid bias of field-effect tube IC1 It reduces, the drain electrode of field-effect tube IC1 and source electrode cut-off, further power input negative terminal P- and power output end anode Terminal Vbus- is disconnected, and is effectively protected the application circuit of next stage.

The utility model structure is simple, and in DC power supply, there are can be protected by over-voltage when a biggish input voltage peak value Protection circuit disconnects power supply, is effectively protected the application circuit of next stage, and device is common device, easily purchases, has a wide range of application.

Claims (5)

1. a kind of DC power supply overvoltage crowbar, it is characterised in that: including first capacitor, the second capacitor, first resistor, Two resistance, first diode, the second diode, triode, field-effect tube, the power input positive terminal P+ and power supply are defeated The first end of the Vbus+ connection of outlet positive terminal, the first capacitor is connect with power input positive terminal P+, and described first The second end of capacitor is connect with power input negative terminal P-, the first end and power input positive terminal of second capacitor The second end of sub- P+ connection, second capacitor is connect with power input negative terminal P-, the first end of the second resistance It being connect with power input positive terminal P+, the second end of the second resistance is connect with the cathode of the second diode, and described The anode of two diodes is connect with the base stage of the triode, the emitter-base bandgap grading of the triode and the power input negative terminal P- connection, the collector of the triode and the first end of first resistor connect, and the second end and power supply of the first resistor are defeated The Vbus+ connection of outlet positive terminal, the cathode of the first diode and the first end of first resistor connect, the one or two pole The anode of pipe is connect with power input negative terminal P-, and the grid of the field-effect tube and the first end of first resistor connect, The source electrode of the field-effect tube is connect with power input negative terminal P-, and the drain electrode of the field-effect tube and power output end are negative Extremely sub- Vbus- connection.

2. DC power supply overvoltage crowbar as described in claim 1, it is characterised in that: the first resistor, second resistance For metalfilmresistor.

3. DC power supply overvoltage crowbar as claimed in claim 2, it is characterised in that: the first capacitor is electrolysis electricity Hold.

4. DC power supply overvoltage crowbar as claimed in claim 3, it is characterised in that: second capacitor is ceramic electrical Hold.

5. DC power supply overvoltage crowbar as claimed in claim 4, it is characterised in that: the field-effect tube is N-channel field Effect pipe.