PROTECTIVE CIRCUIT OF MOSFET

摘要

PROBLEM TO BE SOLVED: To protect the gate oxide film of an MOSFET against breakdown due to overvoltage. SOLUTION: Gate electrodes of a post-stage MOSFETs are connected with the connected drain electrodes of prestage MOSFETs, drain electrodes of the post-stage MOSFETs are connected together, a substrate diode formed on a semiconductor substrate between the prestage drain region and source region is connected between the gate electrode and source electrode of the post-stage MOSFET thus making the breakdown voltage of the substrate diode not higher than a level where the gate oxide film is broken by a voltage being applied between the gate electrode and source electrode of the post-stage MOSFET.