| 摘要 |
PROBLEM TO BE SOLVED: To prevent the reliability degradation of a power supply system in which no current flows from a battery side to a capacitor side as long as a second switching element is not turned on, and furthermore no large current flows from the battery to the capacitor by turning on the second switching element when the voltage of the capacitor is higher than the voltage of the battery. SOLUTION: The power supply system is equipped with a DC generator 1, a capacitor 3 connected to the DC generator 1 at connecting points 2A, 2B, a battery 4 with its one end connected to the connecting point 2A, a series circuit comprising a power connecter 13 having an n-type MOSFET 8 as a switching element connected between the other end of the battery 4 and the connecting point 2A and an n-type MOSFET 5 as a second switching element, and a switch control circuit 19 connected to the connecting points 2A, 2B and the other end of the battery 4 and controlling the turning-on and turning-off of the n-type MOSFET 5. The switch control circuit 19 detects the voltages of the capacitor 3 and the battery 4, and when detects that the voltage of the capacitor 3 is higher than a voltage of the battery 4, the switch control circuit turns on the n-type MOSFET 5. COPYRIGHT: (C)2007,JPO&INPIT
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