| 摘要 |
<p>PURPOSE:To reduce power consumption during stand-by operation by interposing a current control switch between a power source and an external sensor, and turning off the current switch when a microprocessor is placed in a stand-by state. CONSTITUTION:The output current I0 of a power source 1 is supplied to a microprocessor MPU2 and external sensors 31-3n through a constant voltage circuit 7. A current control switch 5 turns off when the output port P of the MPU2 in stand-by mode rises in level. During normal operation, the switch 5 is turned on, so the MPU2 detects inputs from the sensors 31-3n without any hindrance, and during stand-by operation, the current I0 flowing to a closed contact of contacts of the sensors 31-3n is cut off. Consequently, even when a controller using the MPU uses a standby power source as a power source for operation in common, a standby current to some part other than the MPU is cut off as much as possible, so data in the RAM in the MPU are retained for a long period.</p> |
