| 摘要 |
<p>PURPOSE:To provide the power source connection and disconnection system which operates with the output voltage of an AC adapter and selects the voltage optionally to some extent, and need not be changed in design according to the level of the voltage. CONSTITUTION:Once a momentary operation switch SW is turned ON, a transistor(TR) Q1 turns OFF and a high-level signal is inputted to a power source connecting and disconnecting means. The power source connecting and disconnecting means holds its output signal at a low level when the state continues for a certain time. Once the output signal is held at the low level, a power unit (not illustrated) is turned ON. When a switch SW is pressed in the power-ON state, a processor raises a disconnection request to a high level. Once the disconnection request from the processor reaches the high level, a TR Q2 turns ON and a low level is inputted to the power source connecting and disconnecting means. Once the low level is inputted, the power source connecting and disconnecting means outputs the high level immediately and the power unit is turned OFF.</p> |
