| 摘要 |
PURPOSE:To provide a power supply backup circuit in which a normal operation can be sustained at the control section when a battery is disconnected even if a DC/DC converter is not used. CONSTITUTION:Power is fed from a battery 101 through first and second backup capacitors 113, 115 connected in parallel to a microcomputer 118. The first and second capacitors are interconnected through a switching transistor 119 which is fed with an ON command from the microcomputer upon detection of battery voltage drop. Consequently, the first and second capacitors are connected in series to feed backup power to the microcomputer thus sustaining the operation thereof. |
