| 摘要 |
PURPOSE:To prevent malfunction from being generated at the time of applying a power source again by outputting a reset signal to a microcomputer (MPU) when the source voltage of the MPU drops less than a prescribed level in a low power consumption mode in a state where a commercial power source is disconnected. CONSTITUTION:When the commercial power source 1 is disconnected, a source voltage monitoring circuit 6 detects the lowering of the output voltage of a rectifier circuit 2, and outputs an interruption signal VINT to the MPU 5. The MPU 5 sets a processing interruption address, and writes test data on a part of a memory, then, moves a mode to the low power consumption mode. When the source voltage VCC of the MPU 5 drops less than a memory holding guarantee voltage and goes to a voltage in the neighborhood of 0V, the MPU 5, after performing the initializing processing of the memory, restarts an ordinary processing. Therefore, danger in which a processing by using destroyed memory data is continued after recovery of the power source can be evaded. |
