| 摘要 |
PURPOSE:To set a lower output voltage of a battery device by using a transistor (TR) as a charge preventing element for a battery device to decrease the voltage drop between the battery device and a power input terminal of a memory element. CONSTITUTION:A DC power supply device 2 converts a 100V AC voltage supplied from an AC power source 1 into a 5.6V DC voltage and applied the voltage to a positive power input terminal VD of the memory element via a diode 3. If a power failure takes place, the supply of the AC voltage to the DC power source 2 is stopped and an output voltage of the DC power supply device 2 is decreased to 3.5V, then the TR11 is transited to the conductive state. Thus, a 2.9V DC voltage is applied to the input terminal VD of the memory element 4 as a memory holding DC voltage via the TR11 from the battery device 13 after that time. The output voltage of the battery device 13 is set to a value of >=2.8V by using the TR in this way and two dry cells are enough for the purpose. |
