| 摘要 |
PURPOSE:To hold a display device in normal operation as well as a logical circuit when a buzzer is driven by constituting a boosting circuit when the buzzer, etc., is driven and also supplying the discharging voltage of a capacitor for holding the output voltage of a battery to the logical circuit and display device. CONSTITUTION:This system is provided with a boosting circuit which has a capacitor C1 for holding the output voltage VO of a battery 1 and a capacitor C2 for doubling and holding the voltage VO, a heavy load circuit such as a buzzer 5 which when driven, causes the output voltage of the battery 1 to drop, and a logical circuit 3 which normally supplies the output voltage of the battery 1 for the driving. When the buzzer 5 is driven, the charging voltage of the capacitor C1 is switched to the logical circuit 3. Even if the output voltage of the battery 1 drops, the normal operation of the logical circuit 3 is compensated by the discharge voltage of the capacitor C1, and a liquid-crystal display device 4 is driven by discharging voltages of the capacitors C1 and C2 to supply a stable voltage, thus compensating the normal operation of the liquid-crystal display device 4. |
