Overcurrent limiting circuit for electrical or electronic unit in motor vehicle, limits current in power MOSFET when drain-source voltage falls below threshold, based on detected overcurrent

摘要

A main functional part acts as a drive switch which switches a drive current for a load using a power MOSFET, and protects the MOSFET against overcurrent. A shunting and detecting part detects overcurrent by splitting the current fed to the drive switch from the power supply. When the voltage between the drain and source of the power MOSFET falls below a threshold, the main functional part limits the current in the power MOSFET based on the detected overcurrent.