| 摘要 |
A power consumption of a light-receiving device (21) is reduced while a power consumption of a microcomputer (10) that controls the light-receiving device (21) is reduced as well. The microcomputer (10A) is structured to include a drive circuit (11), a sampling/detection circuit (12), a timer (13), a system clock generation circuit (14), a CPU (15), a ROM (16) and a RAM (17). The CPU (15) stops providing the light-receiving device (21) with a power supply by turning off a P channel type MOS transistor (22) with the drive circuit (11) and sets the microcomputer (10) in a standby state for a predetermined period of time. When the microcomputer (10) is released from the standby state, the CPU (15) starts providing the light receiving device (21) with the power supply by turning the P channel type MOS transist (22) or on with the drive circuit (11). |
