Exponential curve type combined turn-off circuit
A shut-off circuit, exponential curve technology, applied in emergency protection circuit devices, electrical components, electronic switches, etc., can solve problems such as poor IGBT turn-off voltage adaptability
Active Publication Date: 2008-01-30
浙江西盈科技股份有限公司
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Problems solved by technology
Although this method has a fast response speed, it has poor adaptability to different IGBT turn-off voltages.
Method used
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[0015] As shown in Fig. 1, in this exponential curve type composite turn-off circuit, its control signal K passes through a phase and level conversion circuit and amplifying circuit in turn to output the drive signal; the phase and level conversion circuit is composed of triode Q1 and Composed of resistor R4 and resistor R3, the control signal K is directly connected to the base of the transistor Q1, the device voltage VDD is also added to the base of the transistor Q1 after passing through the resistor R4, and the circuit voltage VCC is connected to the collector of the transistor Q1 after passing through the resistor R3 , the emitter of the transistor Q1 is connected to the common circuit.
[0016] The protection signal B is parallel-connected to the base of the amplifying circuit through two branches, one of which successively passes through the reverse connection diode D1, the resistor R5, the base of the transistor Q3, the emitter of the transistor Q3 and the reverse conne...
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The invention relates to an IGBT power device drive and over-current protection circuit to solve the technical problem that the power supply circuit to be provided is characterized by high accuracy in current protection, good reliability and low cost. The technic proposal lies in that the control signals of an exponential curve compound turning off circuit sequentially pass a phase, a level converting circuit , an amplification circuit and then output the drive signals; the protection signals pass two branches and are connected with an input end of the amplification circuit, wherein, one branch is reversely connected with a diode D1, and then sequentially passes a base of a transistor Q3; an emitter of the transistor Q3 is reversely connected with a diode D3 and then connected with the input end of the amplification circuit; additionally, the branch is connected with a storage and discharge circuit which consists of a capacitor C1 and a resistor R1 at the base of Q3. The other branch is first reversely connected with the diode D2, and after being connected with a storage and discharge circuit which consists of a capacitor C2, a resistor R2 and a comparator ICIA in series, the branch is also connected with the input end of the amplification circuit.
Description
technical field [0001] The invention relates to a power supply control circuit, in particular to a driving and overcurrent protection circuit of an IGBT power device. Background technique [0002] The current shutdown signal of the existing IGBT drive circuit when a current fault occurs, mostly adopts the direct type, the oblique type and the two-stage type. in: [0003] 1. The direct shutdown method uses a comparator or other control circuit to directly shut off the drive output signal when a current fault occurs (as shown in Figure 2). The disadvantage of this method is that the sudden change of current will cause high overshoot voltage, which will easily cause IGBT overvoltage damage. [0004] 2. The oblique line shutdown mode, some special IGBT driver chips adopt the oblique line shutdown mode: when a fault occurs, the driving voltage drops from the power supply voltage to a certain voltage along a fixed slope within a certain period of time, and then shuts down again....
Claims
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Inventor 王世武梁伟庆龚依民
Owner 浙江西盈科技股份有限公司