Abstract: A voltage conversion apparatus includes a booster circuit, a boost stop circuit, a Zener diode, and a capacitor. The boost stop circuit includes a transistor. When an overvoltage equal to or larger than a breakdown voltage of the Zener diode is output to an output line of the booster circuit, the Zener diode is turned on. Accordingly, the transistor is turned on and a switching element is turned off to stop a boost operation. Further, the capacitor is charged through the Zener diode. Even when the Zener diode is turned off due to a drop in the output voltage after the stop of the boost operation, the transistor maintains its on state for a certain time by discharge of the capacitor. Thus, the stop of the boost operation is continued.

Abstract: A voltage conversion apparatus includes a booster circuit, a boost stop circuit, a Zener diode, and a capacitor. The boost stop circuit includes a transistor. When an overvoltage equal to or larger than a breakdown voltage of the Zener diode is output to an output line of the booster circuit 11, the Zener diode is turned on. Accordingly, the transistor is turned on and a switching element is turned off to stop a boost operation. Further, the capacitor is charged through the Zener diode. Even when the Zener diode is turned off due to a drop in the output voltage after the stop of the boost operation, the transistor maintains its on state for a certain time by discharge of the capacitor. Thus, the stop of the boost operation is continued.

Abstract: A DC-DC converter includes a voltage conversion circuit boosting a voltage of a DC power supply and supplying the voltage to a load, a bypass circuit provided in parallel to the voltage conversion circuit, a drive circuit turning on and off a switching element of the bypass circuit, and a controller outputting a control signal for controlling the voltage conversion circuit and the drive circuit. A diode is connected in parallel to the switching element so as to be oriented toward a forward direction with respect to the DC power supply. A temperature detector of the drive circuit detects temperature of the diode. The drive circuit maintains the switching element in the on state irrespective of the control signal of the controller when the temperature detector detects a temperature greater than or equal to a predetermined value.

Abstract: The present invention provides a power-supply device, which can continuously supply a voltage from a power supply to a load even if a breakdown of a circuit is generated. The power-supply device includes a booster circuit, a normally-closed bypass relay, a CPU, and a switching circuit. A first switch of the switching circuit is turned on by a switching signal from the CPU, and a second switch is turned on by a boosting request signal from a boosting request signal generator. In the case that one of or both the switching signal and the boosting request signal are not input to the switching circuit 14, because a coil of a bypass relay is not energized, a contact turns on, and a voltage is supplied from a DC power supply to the load through the contact.

Abstract: A DC-DC converter includes a voltage conversion circuit boosting a voltage of a DC power supply and supplying the voltage to a load, a bypass circuit provided in parallel to the voltage conversion circuit, a drive circuit turning on and off a switching element of the bypass circuit, and a controller outputting a control signal for controlling the voltage conversion circuit and the drive circuit. A diode is connected in parallel to the switching element so as to be oriented toward a forward direction with respect to the DC power supply. A temperature detector of the drive circuit detects temperature of the diode. The drive circuit maintains the switching element in the on state irrespective of the control signal of the controller when the temperature detector detects a temperature greater than or equal to a predetermined value.

Abstract: The present invention provides a power-supply device, which can continuously supply a voltage from a power supply to a load even if a breakdown of a circuit is generated. The power-supply device includes a booster circuit, a normally-closed bypass relay, a CPU, and a switching circuit. A first switch of the switching circuit is turned on by a switching signal from the CPU, and a second switch is turned on by a boosting request signal from a boosting request signal generator. In the case that one of or both the switching signal and the boosting request signal are not input to the switching circuit 14, because a coil of a bypass relay is not energized, a contact turns on, and a voltage is supplied from a DC power supply to the load through the contact.

Abstract: A power-supply device has a DC power supply, a load, a booster circuit disposed between the DC power supply and the load, wherein the booster circuit supplies a voltage at the DC power supply to the load while boosting the voltage, a bypass element disposed between the DC power supply and the load, wherein the bypass element constitutes a bypass path with respect to the booster circuit, a controller that controls an operation of the booster circuit, a first switching element that drives the bypass element in a first driving path, and a second switching element that drives the bypass element in a second driving path.