| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to extend hours of use and to use an A/D conversion function of a microcomputer without complicating a circuit structure. SOLUTION: A battery voltage Vb of a battery 1 is supplied as an operation power supply Vcc of a microcomputer 7, and an output voltage Va of a regulator 2 is supplied as the reference voltage AVcc of the A/D conversion function of the microcomputer 7. Since the output voltage Va of the regulator 2 is used as the reference voltage AVcc in the A/D conversion function, and the battery voltage Vb of the battery 1 is used as the operation power supply Vcc of the microcomputer 7; a load can continue to be driven until the battery voltage Vb falls below an operation-ensured voltage of the microcomputer 7 without being affected by operation efficiency of the regulator 2. Therefore, since a conventional detection circuit 5 or a switching circuit 4 is not required, the use time can be extended and the A/D conversion function of the microcomputer 7 can be used without complicating the circuit structure. COPYRIGHT: (C)2007,JPO&INPIT |
