igbt drive short circuit protection detection circuit

Abstract

The invention relates to a protection circuit of an IGBT, in particular to an IGBT drive short circuit protection detection circuit. The invention solves the problem that the short-circuit protection time of the existing IGBT drive short-circuit protection detection circuit is affected by the bus voltage, which easily causes the short-circuit protection to be untimely. The circuit includes a first NAND gate U4, a drive board input pulse signal CMD-H processing circuit, an IGBT collector-emitter voltage state acquisition circuit; an output terminal TP-CMD-H of the drive board input pulse signal CMD-H processing circuit and the first A NAND gate U4 is connected to the first input terminal, the drive board input pulse signal CMD-H is connected to the second input terminal of the first NAND gate U4, and the output terminal HZ_Vce of the IGBT collector-emitter voltage state acquisition circuit is connected to the first NAND gate U4 The third input terminal of the NOT gate U4 is connected, and the output terminal of the first NAND gate U4 is used as the output FAILb of the IGBT driving short-circuit protection detection circuit. In the present invention, no matter whether the bus voltage becomes larger or smaller, the response time of the short-circuit protection remains unchanged.

Description

technical field [0001] The invention relates to a protection circuit of an IGBT, in particular to an IGBT drive short circuit protection detection circuit. Background technique [0002] IGBT is more and more widely used in modern power electronics technology. The driving circuit of IGBT is the interface between the main circuit of power electronics and the control circuit. Performance has a big impact. In the switching power supply device, since the IGBT works under the condition of high frequency, high voltage and high current, the IGBT is easily damaged. Therefore, the design of the protection circuit of the IGBT is extremely important. [0003] The short-circuit protection of IGBT usually means that when the inductance in the short-circuit loop is small, the loop current rises rapidly. When the current rises to a certain value (generally 4-6 times the rated current), desaturation occurs. At this time, the IGBT set- The voltage of the emitter is the bus voltage, and the...

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Problems solved by technology

[0009] The invention solves the problem that the short-circuit protection time of the existing IGBT drive short-circuit protection detection circuit is affected by the bus voltage, which easily causes the short-circuit protection to be untimely, and provides an IGBT drive short-circuit protection detection circuit

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