| 摘要 |
PURPOSE:To perform a stable soft start by controlling the period and pulse width of a switching control pulse corresponding to the output voltage of a starting circuit at the time of softly starting. CONSTITUTION:When a step voltage is applied to a starting circuit 8 at the time of softly starting, the output of the circuit 8 gradually increases from 0. At this time control signal is inputted to the bases of transistors Q1, Q2. The width and the period of this control signal correspond to the output voltage of the circuit 8. Accordingly, a pulse width converter 9 is controlled by the output voltage of the circuit 8, the pulse width is reduced when the output voltage of the circuit 8 is low and the period is long, and the pulse width is gradually increased as the period is gradually shortened. In this manner, an output current Io rises gradually from 0, thereby enabling stable softly starting. |
