| 摘要 |
PROBLEM TO BE SOLVED: To reliably perform a protecting operation of a target device using a load for the protecting operation without changing the capacity of a backup capacitor.SOLUTION: An airbag ignition device 1 is supplied with power from a battery 2 via first and second step-up circuits 3,5. The first step-up circuit 3 charges a backup capacitor 4 of which a terminal voltage is detected by a capacitor voltage detection circuit 6, and when the terminal voltage is lowered to a given value or less by disconnecting the battery 2 or another action, the second step-up circuit 5 is caused to step up the voltage. A squib 9 of the airbag ignition device 1 is supplied with power via a diode 7 and MOSFETs 8,10. As a signal for squib-ignition is given from a microcontroller 15, the squib 9 is supplied with a step-up voltage to operate an airbag. |
