| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of radio noise, by stopping the operation of a DC/DC converter with a control means during a prescribed period after a switch-on operation, and charging a backup capacitor through a diode. SOLUTION: A diode 25 is inserted between a signal line provided between the second divider resistor 17 and the non-inversion input terminal of a comparator 22, and the output terminal P3 of a microcomputer 11. The output Q of a D-type flip-flop 23 is latched at a low level by forcibly outputting a high-level signal from the comparator 22 during a prescribed period after the power input of the microcomputer 11. During a fixed period after on-operation of an ignition switch 2, a backup capacitor 9 is charged through the second counter flow blocking diode 8, so that the initial charging voltage ceases to become zero, the off-period of a driving transistor 24 becomes shorter, and generation of current noise is reduced relatively, thus it is possible to prevent generation of radio noise. |
