| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent an on-vehicle battery from becoming dead due to emission of turning off of power supply, even if a car audio device is mounted on a vehicle having no ACC position. <P>SOLUTION: When it is set that there is no ACC position, set time for determining sleep condition detection timing set in advance is counted when mode becomes OFF mode. Voltage A of the on-vehicle battery 30 when starting counting time and voltage B of the on-vehicle battery 30 when the set time elapses are detected. The operation for determining whether the ratio B/A drops below a reference ratio set in advance or not is repeated until the result of determination that the ratio drops below the reference ratio is obtained. When the ratio drops below the reference ratio, mode is set to low consumption electric power mode (sleep mode). <P>COPYRIGHT: (C)2004,JPO</p> |
