Abstract: A power supply control device controls power supply by switching on or off a first semiconductor switch and a second semiconductor switch that are arranged on a current path. A first diode and a second diode are connected between a drain and a source of the first semiconductor switch and the second semiconductor switch, respectively. Cathodes of the first diode and the second diode are arranged downstream and upstream of the respective anode on the current path. If current flows through the current path even though a microcomputer has given an instruction to switch the first semiconductor switch and the second semiconductor switch off, a first drive circuit switches the first semiconductor switch on.

Abstract: A power supply control device controls power supply through a wire. A first current output circuit is configured to output, to a temperature difference circuit, a current that is larger the larger a wire current, which flows through the wire is. The temperature difference circuit is configured to output a voltage that is higher the larger a temperature difference between a wire temperature of the wire and an ambient temperature in the surroundings of the wire is. A drive circuit is configured to interrupt a flow of the wire current if the output voltage of the temperature difference circuit is at least a voltage threshold.

Abstract: A power supply control device controls power supply from a DC power source to a load, by turning on or off a MOSFET. A current regulation circuit regulates a current flowing through a device resistor to a current proportional to a voltage between the drain and the source of the MOSFET. A drive circuit turns off the MOSFET when a voltage across a resistor circuit exceeds a predetermined voltage. The on-resistance of the MOSFET varies according to an ambient temperature of the MOSFET. The resistance of the resistor circuit varies in a direction different from a direction in which the on-resistance of the MOSFET varies, according to the ambient temperature of the MOSFET.

Abstract: A power supply control device controls power supply by switching on or off a first semiconductor switch and a second semiconductor switch that are arranged on a current path. A first diode and a second diode are connected between a drain and a source of the first semiconductor switch and the second semiconductor switch, respectively. Cathodes of the first diode and the second diode are arranged downstream and upstream of the respective anode on the current path. If current flows through the current path even though a microcomputer has given an instruction to switch the first semiconductor switch and the second semiconductor switch off, a first drive circuit switches the first semiconductor switch on.

Abstract: Provided is an on-board device and a vehicle communication system that can expand the transmission range of signals that are transmitted from transmission antennas of the on-board device. An on-board device transmits signals to a portable device, from a plurality of first to fourth LF transmission antennas that are provided for a vehicle at positions that are separate from each other. The on-board device includes a transmission unit that transmits the signals from the first to fourth LF transmission antennas such that a transmission range in which the portable device can receive the signals is a range around the vehicle. The transmission unit substantially simultaneously transmits the signals from two or more transmission antennas among the first to fourth LF transmission antennas, to expand the transmission range.