CN201682411U

CN201682411U - Switch control circuit with short circuit protection

Info

Publication number: CN201682411U
Application number: CN 201020174109
Authority: CN
Inventors: 李建奇; 李晓峰; 杨如曙; 王文虎; 杨民生
Original assignee: Hunan University of Arts and Science
Current assignee: Hunan University of Arts and Science
Priority date: 2010-04-29
Filing date: 2010-04-29
Publication date: 2010-12-22
Anticipated expiration: 2020-04-29

Abstract

The utility model provides a switch control circuit with short circuit protection, which comprises a drive circuit and a short circuit protective circuit of an insulated gate bipolar type transistor (Q1), wherein the short circuit protective circuit consists of a resistor (R13) and a diode (D2) which are in series connection between a collector electrode of a transistor (T4) and a drain electrode of the transistor (Q1), a divider resistance (R12) is in series connection between a single power supply and a source electrode of the transistor (Q1), a divider resistance (R11) is in series connection between the source electrode of the transistor (Q1) and the ground, a base electrode and the collector electrode of the transistor (T4) are connected with a transistor (T5), and a transmitting electrode of the transistor (T5) is in series connection with a diode (D1) and a resistor (10) and then connected with the source electrode of the transistor (Q1). The switch control circuit with short circuit protection can effectively prevent the transistor (Q1) from being damaged owing to overcurrent, consists of discrete components, and has the advantages of stable performance and lower cost.

Description

ON-OFF control circuit with short-circuit protection

Technical field

The utility model relates to a kind of control circuit, especially relate to a kind of oxide-semiconductor control transistors conducting or by and have an ON-OFF control circuit of short-circuit protection.

Background technology

Insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) by the device that is composited of ambipolar power transistor and MOSFET, so it has both common a bit, i.e. multiple advantages such as input impedance height, speed is fast, switching frequency is high, Heat stability is good, drive circuit letter, single ampacity are big, blocking voltage height.Therefore, in present power electronic technology, obtain more and more widely application.Yet the drive circuit of IGBT is the interface between power electronics main circuit and the control circuit, is the important step of power electronic equipment, and the performance of whole device is had very big influence.Adopt well behaved drive circuit, can make power electronic device be operated in comparatively ideal on off state, shorten switching time, reduce switching loss, operational efficiency, reliability, the fail safe of installing all had important meaning.But in switching power unit,, make IGBT damage easily because it is operated under the condition of high pressure, big electric current.

The utility model content

The utility model proposes a kind of oxide-semiconductor control transistors conducting or by and have an ON-OFF control circuit of short-circuit protection, be operated in the technical problem of damaging easily under the condition of high pressure, big electric current to solve IGBT.

For solving technical problem of the present utility model, the utility model discloses a kind of ON-OFF control circuit with short-circuit protection, and it comprises: the drive circuit of insulated gate bipolar transistor Q1 and short-circuit protection circuit.

Wherein, drive circuit comprises: the optocoupler U1 of receiving inputted signal, and transistorized collector electrode and emitter couple the collector and emitter of transistor T 4 respectively among this optocoupler U1, and the base stage of transistor T 4 serial connection RC circuit is connected with single supply; Constitute three transistor Ts 1, T2 and T3 of driving pulse amplifying circuit, wherein the base stage of transistor T 1 is connected with the base stage of transistor T 4, and collector series connection resistance R 7 connects single supply; And the output series resistor R14 of pulse amplifying circuit connects the grid of transistor Q1; Between the source electrode of transistor Q1 and ground, be connected filter capacitor C2;

Short-circuit protection circuit comprises: be serially connected in resistance R 13 and diode D2 between the drain electrode of the collector electrode of transistor T 4 and transistor Q1; Between the source electrode of single supply and transistor Q1, be connected in series divider resistance R12, between the source electrode of transistor Q1 and ground, be connected in series divider resistance R11; The transistor T 5 that base stage is connected with the collector electrode of transistor T 4, the emitter serial connection diode D1 and the resistance R 10 of this transistor T 5 is connected the source electrode of transistor Q1 afterwards.

Wherein, between grid-source electrode of transistor Q1 and meet two bi-directional voltage stabilizing pipe D4 and D5.

Wherein, transistor T 1, T2, T3, T4 and T) be NPN transistor.

Compared with prior art, the utlity model has following beneficial effect:

ON-OFF control circuit that the utility model provides adopts single supply, and (+24V) power supply just can provide for IGBT+15V guarantees turning on and off of IGBT, reduced power supply with-9V two-way driving voltage; In addition, this circuit also has short-circuit protection function, and when the IGBT drain current was excessive at that time, protective circuit worked, and limit drain current prevents that IGBT from damaging because of overcurrent timely.Therefore, the utility model adopts discrete component to form, and has stable performance and lower-cost advantage.

Description of drawings

Fig. 1 is an electrical block diagram of the present utility model.

Embodiment

Insulated gate bipolar transistor (IGBT) is the voltage-type control device, and IGBT is safe and reliable to turn on and off efficiently in order to make, and provides short-circuit protection to be very important to IGBT.

As shown in Figure 1.This switching circuit comprises: drive circuit and the short-circuit protection circuit of insulated gate bipolar transistor (IGBT) Q1.

This drive circuit comprises: input signal Uin is by current-limiting resistance R1 input optocoupler U1, and transistorized collector electrode and emitter are connected the collector and emitter of transistor T 4 respectively respectively among the optocoupler U1 by series resistor R4 and R5; And the base stage series resistor R3 of transistor T 4 is connected with single supply (Vcc=24V) with the RC circuit that capacitor C 1 constitutes; Transistor T 1～T3 constitutes the driving pulse amplifying circuit, and the base stage of transistor T 1 is connected with the base stage of transistor T 4, and the output series resistor R14 of pulse amplifying circuit connects the grid (G) of IGBT; Crystal T1 and resistance R 7 constitute an emitter follower, and this emitter follower provides a current source fast, has reduced turning on and off the time of power tube; Be connected the capacitor C 2 between IGBT source electrode (S) and the ground, this capacitor C 2 is used for the filtering high-frequency signal.

Therefore, drive the main circuit employing and recommend the way of output, reduced the output impedance of drive circuit effectively, can improve driving force, make it to be suitable for the driving of high-power IGBT to greatest extent to the very strong driving voltage of IGBT output.

Short-circuit protection circuit comprises: be serially connected in resistance R 13 and the diode D2 of transistor T 4 collector electrodes and IGBT drain electrode between (D), wherein diode D2 adopts fast recovery diode, and the high voltage when preventing that IGBT from turn-offing on its collector electrode is scurried into drive circuit; Resistance R 13, diode D2, resistance R 6 and T4 constitute the short-circuit signal testing circuit; In order to prevent that static from mislead power device, between grid-source electrode of IGBT and meet bi-directional voltage stabilizing pipe D4 and D5; Resistance R 12 and R11 dividing potential drop constitute a negative voltage, when turn-offing IGBT, for providing between its grid-source-voltage of 9V, IGBT are turn-offed fast; The transistor T 5 that base stage is connected with transistor T 4 collector electrodes, the source electrode that the emitter serial connection diode D1 of this transistor T 5, resistance R 10 connect IGBT afterwards.

Therefore, saturated principle is moved back in short-circuit protection circuit utilization drain electrode, when the generation drain current is excessive, reduces the driving voltage of IGBT, before IGBT damages, with its shutoff, thereby has protected IGBT.

During operate as normal: when input signal Uin is high level signal, optocoupler U1 ends, transistor T 1 and T3 conducting, and transistor T 2 ends, this moment, the grid voltage of IGBT was 0V, and because the dividing potential drop effect of resistance R 11 and R12, the voltage of the source electrode of IGBT is+9V, so the voltage of generation-9V between grid-source turn-offs IGBT fast.

When input signal Uin is low level signal, optocoupler U1 conducting, transistor T 1, T3 end, and transistor T 2 conductings, this moment, the grid voltage of IGBT was+24V, the voltage of source electrode is+9V, thus between grid-source the voltage of generation+15V, make IGBT open-minded fast.

When producing short trouble: during when the IGBT conducting, transistor T 4 ends, when the load of inverter circuit is short-circuited or during upper and lower bridge arm direct pass and when making the IGBT drain current excessive, the IGBT drain electrode is moved back saturated, the current potential of transistor T 4 collector electrodes is raise, thereby make transistor T 5 conductings, make the current potential of transistor T 5 emitters raise diode D1 conducting; Because the voltage of capacitor C 2 can not suddenly change, continue to raise according to index law, the IGBT source voltage is raise gradually, rising along with the IGBT source voltage, voltage between IGBT grid-source electrode is step-down even shutoff fully gradually, thereby has limited the drain current of IGBT, so avoided damaging GIBT because of the drain electrode overcurrent, after fault was got rid of, entire circuit can be recovered operate as normal again automatically.

To sum up, ON-OFF control circuit that the utility model provides adopts single supply (24V) power supply, just can provide for IGBT+15V guarantees turning on and off of IGBT, reduced power supply with-9V two-way driving voltage; High speed photo coupling U1 realizes the electrical isolation of input/output signal, can make drive circuit and control circuit want strict the isolation on current potential, and suitable frequency applications occasion; In addition, this circuit also has short-circuit protection function, and when the IGBT drain current was excessive at that time, protective circuit worked, and limit drain current prevents that IGBT from damaging because of overcurrent timely.Therefore, the utility model adopts discrete component to form, and has stable performance and lower-cost advantage.

Claims

1. ON-OFF control circuit with short-circuit protection comprises it is characterized in that the drive circuit and the short-circuit protection circuit of insulated gate bipolar transistor (Q1):

Drive circuit comprises: the optocoupler of receiving inputted signal (U1), and transistorized collector electrode and emitter couple the collector and emitter of transistor (T4) respectively in this optocoupler (U1), and the base stage of transistor (T4) serial connection RC circuit is connected with single supply; Constitute three transistors (T1, T2 and T3) of driving pulse amplifying circuit, wherein the base stage of transistor (T1) is connected with the base stage of transistor (T4), and collector series connection resistance (R7) connects single supply; And the output series resistor (R14) of pulse amplifying circuit connects the grid of transistor (Q1); Between the source electrode of transistor (Q1) and ground, be connected filter capacitor (C2);

Short-circuit protection circuit comprises: be serially connected in resistance (R13) and diode (D2) between the drain electrode of the collector electrode of transistor (T4) and transistor (Q1); Between the source electrode of single supply and transistor (Q1), be connected in series divider resistance (R12), between the source electrode of transistor (Q1) and ground, be connected in series divider resistance (R11); The transistor (T5) that base stage is connected with the collector electrode of transistor (T4), the emitter serial connection diode (D1) and the resistance (R10) of this transistor (T5) is connected the source electrode of transistor (Q1) afterwards.

2. according to the described ON-OFF control circuit of claim 1, it is characterized in that, between grid-source electrode of transistor (Q1) and connect two bi-directional voltage stabilizing pipes (D4 and D5) with short-circuit protection.

3. according to the described ON-OFF control circuit of claim 1, it is characterized in that transistor (T1, T2, T3, T4 and T5) is NPN transistor with short-circuit protection.