| 摘要 |
PROBLEM TO BE SOLVED: To cut off a battery from an electronic apparatus automatically when the output voltage of the battery drops and not to supply a power to the electronic apparatus at all by a method wherein a power supply voltage is monitored and compared with a reference voltage to control the supply or cut-off of the power supply voltage. SOLUTION: If a transistor 11 is turned on, the output voltage of a battery 1 is applied to a load circuit 3, a reference voltage source 14 and a comparator 15 through the transistor 11 as a power supply voltage and the load circuit 3, the reference voltage source 14 and the comparator 15 are operated. The power supply voltage supplied from the transistor 11 is divided by resistors 12 and 13 and the divided voltage value is compared with the output of the reference voltage source 14 by the comparator 15. The output voltage of the battery 1 is monitored by a voltage monitoring means 52 and, when the voltage drops, a power supply cut-off means 51 is operated. With this constitution, the decline of the output voltage of the battery 1 is automatically detected and the battery 1 can be cut off from the load circuit 3 without using a control circuit. |
