POWER SUPPLY DEVICE FOR AUTOMOTIVE ELECTRICAL EQUIPMENT, AND AUTOMOTIVE ELECTRICAL EQUIPMENT UNIT

PROBLEM TO BE SOLVED: To prevent energy loss at normal time, in a power supply device for automotive electrical equipment provided with a capacitor device that supplies power to the electrical equipment when the emergency is caused in the battery.SOLUTION: The power supply device includes: a capacitor device 14 connected to a power supply line 26 in parallel with the battery 24; a diode 16 that is connected from the capacitor device 14 on the battery side power supply line 26 so that the direction from the battery 24 to the automotive electrical equipment 28 may become a forward direction; a bypass circuit 22 that is composed of the diode 16 and a switch portion 32 connected in parallel therewith through a bypass line 30; a current detection circuit 18 that detects the forward direction current that flows to the automotive electrical equipment 28 side and the reverse direction current that flows to the battery 24 side, and outputs the detection signal; and a logic circuit 20 that receives the detection signal and controls the switch portion 32. The logic circuit 20 receives the detection signal of the reverse direction current and performs OFF control of the switch portion 32, and receives the detection signal of the forward direction current and performs ON control of the switch portion 32.