| 摘要 |
PURPOSE:To approximately keep the start time constant independently of the fluctuation of a supply voltage. CONSTITUTION:When charging of a filter capacitor C in the uncharged state is started, a transistorTR Q7 of a quick charging circuit A is made conductive to quickly charge this capacitor by a second resistance R2. When a charging voltage Vp rises to a voltage lower than a supply voltage Vcc by a Zener voltage Vz, quick charging due to the second resistance is switched to charging due to a first resistance R1 to gradually charge the filter capacitor C; and when the terminal voltage of the capacitor C reaches a detection voltage, TRs Q1 and Q2 for start are cut off to start power TRs Qp1 and Qp2. |
