Patent ID: 9455711
Filing Date: 2016-09-27
CPC Classification: H03K

Claim Text:
1. A semiconductor integrated circuit device, including a high-voltage MOSFET in a semiconductor region arranged on a main surface of a semiconductor substrate via an insulating substrate, the semiconductor integrated circuit device comprising: a first high-voltage MOSFET of a first conductive type having a source terminal, a drain terminal, and a gate terminal; a second high-voltage MOSFET of the first conductive type having a source terminal connected to the source terminal of the first high-voltage MOSFET, a gate terminal connected to the gate terminal of the first high-voltage MOSFET, and a drain terminal; and a first floating gate voltage control circuit configured to operate at a voltage within the range between a voltage exceeding a ground voltage and a voltage of 5 V or lower as a power-supply voltage and control on/off states of the first high-voltage MOSFET and the second high-voltage MOSFET according to a first control signal, the first floating gate voltage control circuit being connected to a source terminal of the first high-voltage MOSFET and a gate terminal of the first high-voltage MOSFET, and when turning on the first high-voltage MOSFET and the second high-voltage MOSFET, the first floating gate voltage control circuit setting a voltage in the source terminal of the first high-voltage MOSFET as a reference voltage, adding a floating voltage corresponding to the power-supply voltage to the reference voltage, and supplying the floating voltage to the gate terminals of the first high-voltage MOSFET and the second high-voltage MOSFET.