CN203457038U

CN203457038U - IGBT driving optical coupler protection circuit

Info

Publication number: CN203457038U
Application number: CN201320562460.4U
Authority: CN
Inventors: 钱富全; 王鹏
Original assignee: SHENYANG SANYO ELEVATOR CO Ltd
Current assignee: SHENYANG SANYO ELEVATOR CO Ltd
Priority date: 2013-09-11
Filing date: 2013-09-11
Publication date: 2014-02-26
Anticipated expiration: 2023-09-11

Abstract

Provided is an IGBT driving optical coupler protection circuit comprising a resistor Re and two filtering capacitors C1 and C2. The Re is loaded between a ground pin of a driving optical coupler and a ground signal of an IGBT driving unit, and the filtering capacitors C1 and C2 are loaded at a power supply terminal of the driving optical coupler. Spike oscillation can be prevented from entering the driving optical coupler in an IGBT switching state by lowpass filtering formed by the resistor Re and the filtering capacitors C1 and C2, the protection driving optical coupler can be free from interferences of the spike oscillation in a driving process of the switching of an IGBT, over-high spike pulses can also be prevented from entering the driving optical coupler, the pin or an internal circuit of the driving optical coupler can be prevented from being damaged, the stability of a driving circuit can be achieved, and the reliability of the circuit is improved.

Description

A kind of IGBT drives optocoupler protective circuit

Technical field

The utility model relates to a kind of driving optocoupler protective circuit for insulated gate bipolar triode (Insulated Gate Bipolar Transistor, IGBT).

Background technology

Insulated gate bipolar triode (Insulated Gate Bipolar Transistor, IGBT) is the multiple device of MOSFET and bipolar transistor.The advantage that its existing power MOSFET input impedance is high, operating rate fast, easily drive, there is again the withstand voltage height of bipolar Darlington power transistor (GTO), current capacity large, at a high speed and the superperformance such as saturation voltage is low, can work in tens KHz frequency ranges, therefore obtained application very widely in field of power electronics, for example be widely used in frequency converter, in the equipment such as ups power, motor adjustment and inversion welding.

IGBT of the prior art drive and protective circuit as shown in Figure 1: comprise and receive the logic control element 1 that drives pwm control signal output; Be connected with described logic control element 1, and according to the drive control signal of the logic control element output receiving, drive the driver element 2 of IGBT; And detect power input voltage, IGBT output current etc. and export corresponding protection control signal with the protected location 3 of protection IGBT safety.Wherein the output signal of driver element 2 and the grid of IGBT are connected to drive IGBT to realize opening and turn-offing of IGBT, and the ground end of driver element are connected to form current circuit with the emitter of IGBT.Wherein the current direction of IGBT when opening as shown in Figure 2.As seen from Figure 2, this drive circuit connected mode can make directly to flow to driving optocoupler through the electric current of IGBT, but in the switching process of IGBT, because the impact of parasitic capacitance can form certain spike vibration, this spike vibration is directly added in and drives optocoupler pin, can disturb the damage that even causes driving optocoupler pin or internal circuit to driving optocoupler internal circuit to produce.

Summary of the invention

In order to solve the spike vibration that existing IGBT drives and protective circuit produces in IGBT switching process, enter into driving optocoupler; to driving optocoupler internal circuit to produce, disturb the problem that drives optocoupler pin or internal circuit of even damaging, the utility model provides a kind of novel IGBT to drive optocoupler protective circuit.

The purpose of this utility model is achieved through the following technical solutions: a kind of IGBT drives optocoupler protective circuit; it is characterized in that: by a resistance R e, two filter capacitor C1, C2, formed; described Re is carried in and drives between the ground pin of optocoupler and the earth signal of IGBT driver element, and described filter capacitor C1, C2 is carried in the power end that drives optocoupler.

The beneficial effects of the utility model: the protective circuit for IGBT driving optocoupler of the utility model design; the low-pass filtering forming by resistance R e and filter capacitor C1, C2; can eliminate the spike vibration producing and enter into driving optocoupler under IGBT on off state; make protection drive optocoupler in driving IGBT switching process, not to be subject to the interference of this spike vibration; also can avoid too high spike to enter into driving optocoupler; damage and drive optocoupler pin or internal circuit; be conducive to realize the stability of drive circuit, improve its reliability.

Accompanying drawing explanation

Fig. 1 is that IGBT of the prior art drives and protective circuit schematic diagram.

The current direction schematic diagram of Fig. 2 prior art IGBT when opening.

Fig. 3 has loaded the schematic diagram of the utility model driving optocoupler protective circuit.

Fig. 4 is the circuit theory diagrams of the utility model specific embodiment.

Embodiment

In order to solve the spike vibration that existing IGBT drives and protective circuit produces in IGBT switching process, enter into driving optocoupler, to driving optocoupler internal circuit to produce, disturb the problem that drives optocoupler pin or internal circuit of even damaging, load driver optocoupler protective circuit 4 on the basis of the IGBT of Fig. 1 prior art driving and protective circuit, drive optocoupler protective circuit 4 by a resistance R e, two filter capacitor C1, C2 forms, described Re is carried in and drives between the ground pin of optocoupler and the earth signal of IGBT driver element, described filter capacitor C1, C2 is carried in the power end that drives optocoupler.

As shown in Figure 4, the optocoupler model in this figure is that ACPL-332J drives optocoupler to its concrete application examples.Driving optocoupler protective circuit is to form low pass filter by protective resistance Re and driving optocoupler input power filter capacitor C1, C2, thereby realize, the filtering protection of spike is driven to optocoupler without interruption or damage.

Its operation principle is as follows: if do not add this driving optocoupler protective resistance Re; the spike vibration meeting producing in IGBT switching process is constantly carried out charging and discharging process by circuit to capacitor C 4; can moment the pin voltage that drives optocoupler 14 pin or 16 pin be lifted to higher or be pulled down to lower voltage; easily to driving optocoupler internal circuit to produce, disturb, even cause driving the damage of optocoupler pin or internal circuit.

The size of Re generally determines according to filter capacitor C1, C2, and in the present embodiment, protective resistance Re should select the resistance (10 of larger impedance

Figure 2013205624604100002DEST_PATH_IMAGE001

～1K

, recommendation is 100

).Filter capacitor C1, C2 are equivalent to path for the spiking of high frequency; much smaller than entering into the input impedance Re that holds pin; so the spike of high frequency will be released by C1, C2 electric capacity; only retain low frequency signal and enter into driving optocoupler; thereby protection drives optocoupler pin or internal circuit is interference-free or damage, plays driving the object of optocoupler protection.

Claims

1. an IGBT drives optocoupler protective circuit; it is characterized in that: by a resistance R e, two filter capacitor C1, C2, formed; described Re is carried in and drives between the ground pin of optocoupler and the earth signal of IGBT driver element, and described filter capacitor C1, C2 is carried in the power end that drives optocoupler.