| 摘要 |
PROBLEM TO BE SOLVED: To continue an operation tentatively even if a battery is worn by a method wherein, if the voltage of a first battery which supplies a required power supply voltage to a whole electronic circuit is lowered below a required voltage, the first battery is switched to a second battery which supplies the required power supply voltage to the whole electronic circuit. SOLUTION: The terminal A of a switch 26 is connected to the (+) side of a first battery 20 and the terminal B of the switch 26 is connected to the (+) side of a second battery 24. The common terminal C of the switch 26 is connected to the terminal B of a switch 22. The switching of the contacts of the switch 26 is controlled by a control signal CHGSIGI from a CPU 10. If the CPU 10 judges that the output voltage of the first battery 20 is lowered below a transition voltage VTHI the level of the control signal CHGSIGI is turned to H. With this constitution, the common terminal C of the switch 26 is connected to the terminal B and the output of the second battery 24 is supplied to the respective circuit elements of an electronic circuit as a power supply voltage VCC2 through the switch 22 and a power supply switch 23. |
