Crowell & Moring LLP
Circuit for protecting a load from an overvoltage
A circuit for protecting a load from an overvoltage can be integrated together with the load on the same chip by an MOS transistor manufacture process. This overvoltage protecting circuit is composed of a surge protection circuit, an overvoltage detecting circuit and a switching circuit. The surge protection circuit including two MOS transistors operates so that a surge voltage applied to a power supply receiving terminal is clamped by virtue of the source-drain breakdown voltage of the two MOS transistors, thereby absorbing the surge energy. The overvoltage detecting circuit including two MOS transistors operates so that a DC voltage supplied from the surge protection circuit is monitored with the source-drain voltage of the two MOS transistors taken as a reference voltage, thereby detecting an overvoltage. An overvoltage detection output brings an MOS transistor of the switching circuit into a turned-off condition to protect the load.
Hitachi Car Engineering Co., Ltd. Hitachi, Ltd.
H H
H01L H02H
inventional inventional
Hiromichi Atsushi Kohei Keiji Tatsumi Masahiro Fumio
Yamada Miyazaki Sakurai Hanzawa Yamauchi Matsumoto Murabayashi