IGBT overcurrent protection circuit

Abstract

The invention discloses an IGBT overcurrent protection circuit. The IGBT overcurrent protection circuit comprises an overcurrent signal generation circuit and a CPLD chip, wherein the overcurrent signal generation circuit generates an overcurrent signal according to the current of the collector of an IGBT, and the CPLD chip makes judgment and carries out outputting to block an IGBT drive signal according to the intensity of the overcurrent signal, and a DSP control chip reads the counting value of the CPLD chip and generates a reset signal. The IGBT overcurrent protection circuit can feed an overcurrent fault signal back to a DSP without the dependence on current detection through the chip; under the extreme condition that the DSP shuts down, a drive signal of the IGBT can be reliably blocked, and therefore safety of a power system is guaranteed.

Description

technical field [0001] The invention relates to an IGBT overcurrent protection circuit, which belongs to the field of overcurrent protection. Background technique [0002] In a high-voltage and high-power inverter power supply, the IGBT often bears a relatively large current, which can reach more than 100A. IGBT overcurrent is the main cause of damage to IGBT. Overcurrent protection is not only directly related to the working performance and operation safety of the IGBT device itself, but also affects the performance and safety of the entire power system. The success of IGBT applications depends largely on the quality of the overcurrent protection circuit. [0003] The voltage U between the IGBT collector and emitter CE It is numerically equal to the product of the collector current and the on-state impedance of the device. Therefore, once the IGBT overcurrent, U CE will increase with increasing collector current. According to this characteristic, the common overcurrent...

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Problems solved by technology

[0004] This detection method uses discrete components with low integration

And below the threshold voltage, the current flowing through the IGBT may have exceeded the rated current. If this state lasts for too long, the IGBT may be locked and cause damage to the IGBT.

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