| 摘要 |
PURPOSE:To increase the stability of an output voltage, by suppressing a rush current at the application of power supply, through the gradual increase in the output voltage at the start of power application, in a switching regulator. CONSTITUTION:When a power supply is connected between input terminals 2a and 2b, transistors (TRs)Q1 and Q2 turn on and Q3 and Q4 turn on, then most of current flows to an output stage capacitor C2 and a smoothing capacitor C3 as a charging current. When the voltage of the capacitor C2 reaches a prescribed level or more, a Q5 turns on and Q1, Q2, Q3 and Q4 sequentially turn off. Thus, the base current of the Q5 is interrupted, the Q5 turns off, and the Q1-Q4 sequentially turn on, a charging current flows to the capacitors C2 and C3, and the Q5 again turns on. Since some charges are stored in the capacitor C2, an output voltage Vb is increased by some amount. Thereafter, the similar operation is repeated and the output voltage Vb is gradually increased. |
