| 摘要 |
PURPOSE:To reduce the size and weight of a DC-DC converter, by providing a means for stopping the operation of the converter at a voltage set lower than a voltage at which the operation of an igniter for an internal combustion engine is stopped when the voltage of a battery has exceeded a prescribed level. CONSTITUTION:The operation stop voltage of a DC-DC converter 30 is set at about 17V, which is lower than the ignition stop voltage (about 28-33V) of spark plugs 6-9. When an engine is started at a voltage of 24V, sparks are made on the plugs 6-9 only by an IC ignition unit 3 and the DC-DC converter 30 does not operate. For that reason, the capacity of the power transistor 16 of the DC-DC converter 30 does not need to be large and the transistor does not operate at a voltage of 17V or more. The power transistor 16 is thus prevented from being broken down by a surge superposed on power lines. |
