| 摘要 |
PURPOSE:To obtain a simple and inexpensive power supply device for a camera, etc. without using an expensive FET by connecting a bipolar transistor in parallel to a resistance with a voltage stabilized circuit consisting of a resistance and a capacitor. CONSTITUTION:When a switch S1 is turned on before a capacitor 102 is charged, a current flows to the base of a bipolar transistor TR104 via a resistance 103. Thus the TR104 is turned on and the current given from a battery 91 is applied to the capcitor 102 through the TR104. Then the capacitor 102 is charged quickly. When the charging voltage of the capacitor 102 reaches a prescribed level, the base-emitter voltage of the TR104 is dropped. Then the TR104 is turned off and the stable voltage is applied to a part 94a where the voltage stabilization is needed from the capacitor 102. Furthermore no external pin is needed unlike a circuit using an FET. This facilitate the easy conversion of this power supply device into an IC. |
