| 摘要 |
PROBLEM TO BE SOLVED: To provide a power switching device that ensures power switching with a reduced voltage fluctuation.SOLUTION: The power switching device includes: a second power supply connection section connected with a second power supply; a first power supply connection section connected with a first power supply having a higher voltage than the second power supply; a power output section connected with a load circuit; a diode connecting an output terminal of a constant voltage circuit to the power output section; the constant voltage circuit inserted between the first power supply connection section and the diode to step down the voltage of the first power supply to a voltage higher than the voltage of the second power supply by a forward voltage drop of the diode; a MOS switch for turning on/off a connection of the second power supply connection section to the power output section; and a comparison circuit that is powered from the first power supply connection section, that compares the output voltage of the constant voltage circuit with the voltage of the second power supply connection section or the power output section, and that applies the voltage of the first power supply to the MOS switch for turning off the MOS switch, when the output voltage of the constant voltage circuit is higher than the voltage of the second power supply connection section or the power output section. |
