Rohm Co., Ltd.

Rohm Co., Ltc.

Nobuhiro Nishikawa

Koichi Inoue

Hiroki Inoue

Shinsuke Takagimoto

Takayuki Nakashima

Yoshiyuki Hojo

Kazuhiko Nishimura

Yoshihisa Hiramatsu

Kou Takemura

A power-supply device has a first power supply circuit adapted to generate from an input voltage a first output voltage and a second power supply circuit adapted to generate from the first output voltage a second output voltage. The second power supply circuit monitors the first output voltage to check if it is higher than a first threshold voltage, and also monitors the first power-supply circuit to check if it has started operation for generating the first output voltage, so that the second power supply circuit stays on stand-by, even when the first output voltage is higher than the first threshold voltage, until the first power supply circuit starts operation for generating the first output voltage.

Power supply device, vehicle-mounted device, and vehicle

A regulator circuit is provided which suppresses a variation in output voltage upon occurrence of a variation in input voltage or output current without any increase in steady-state power consumption.

Regulator circuit capable of detecting variations in voltage

A semiconductor integrated circuit device has a MOS transistor Mincluding a parasitic diode Dxfor preventing a reverse current due to a parasitic diode Dxof a MOS transistor M. The semiconductor integrated circuit device further has a voltage setting circuitfor turning the MOS transistor Moff in a reversely biased state, and an anti-reverse-current elementfor preventing a reverse current from flowing through the voltage setting circuitin a reversely biased state. In normal operation, a direct-current voltage within the withstand voltage range of the MOS transistor Mis fed to the gate thereof according to the voltage applied to the conductive terminalof the MOS transistor M

Semiconductor integrated circuit device configured to prevent the generation of a reverse current in a MOS transistor

A power supply device that feeds electric power to an output terminal that is to be connected to a load has first and second PNP-type transistors having their emitters connected to a supplied power line. The collector of the first transistor is connected to the output terminal, and is connected also through two serially connected resistors to ground. An operational amplifier controls the first and second transistors in such a way that the voltage at the node between the two serially connected resistors is kept equal to a setting voltage. To achieve this, a control current is fed to the bases of the first and second transistors. In accordance with the collector current of the second transistor, a limiter circuit limits the output current of the first transistor. The limiter circuit controls the first transistor through the operational amplifier. Between the collectors of the first and second transistors, a capacitor is connected. This capacitor keeps the collector voltage of the second transistor high so as to make the limiter circuit operate when the power supply device is started up or the load is short-circuited.

Growing community of inventors

Kyoto, Japan

Nobuhiro Nishikawa