A current sampling circuit for intelligent power module

Abstract

A current sampling circuit for an intelligent power module comprises three upper bridge arms and three lower bridge arms which correspond to the upper bridge arms, wherein the upper bridge arms and the lower bridge arms are respectively connected with grid electrodes of corresponding insulated gate bipolar transistor (IGBT) tubes by resistors, a collector phase of the IGBT on each upper bridge arm is connected with a high-voltage point, a collector phase of the IGBT on each lower bridge arm is connected with an input end of the current sampling circuit, the current sampling circuit is provided with a first output end and a second output end as well as an input / output end grounding potential of the current sampling circuit. Besides the traditional over-current protection function, the current sampling circuit also has an over-temperature protection function, so that the intelligent power module can be guaranteed to work under a safety temperature; when the temperature is abnormal, even if the current is not abnormally extremely high, the intelligent power module can be stopped working, so that the damage of the intelligent power module under the high temperature and large current can be effectively avoided, the explosion possibility of the intelligent power module can be greatly reduced, the safety of subsequent circuits and devices can be guaranteed, and the fire potential danger of the device can be eliminated.

Description

technical field [0001] The invention relates to a current sampling circuit for an intelligent power module, in particular to current and temperature detection in an intelligent power module (IPM), and also to a compressor control technology for an inverter air conditioner. Background technique [0002] Intelligent Power Module, or IPM (Intelligent Power Module), is a power drive product that combines power electronics and integrated circuit technology. The intelligent power module integrates the power switching device and the high-voltage driving circuit, and has built-in fault detection circuits such as overvoltage, overcurrent and overheating. On the one hand, the intelligent power module receives the control signal from the MCU to drive the subsequent circuit to work, and on the other hand, it sends the system status detection signal back to the MCU. Compared with traditional discrete solutions, intelligent power modules have won an increasing market due to their advanta...

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Problems solved by technology

[0007] Because milliohm resistors are usually made of materials with a very small positive temperature coefficient, when the temperature of the smart power module rises sharply due to poor heat dissipation, the resistance value of the milliohm resistor will only increase slightly. When the temperature is abnormal, the protective effect can only be produced when the current reaches a fixed value; but the current capability of the power device decreases with the rise of the junction temperature, so when the temperature of the intelligent power module rises sharply, the current sampling circuit will not be able to advance Carry out overcurrent protection for the intelligent power module, causing the intelligent power module to be damaged due to abnormally high temperature, and will explode in severe cases

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