| 摘要 |
PURPOSE:To provide stable overcurrent drooping characteristic by providing suppressing means for suppressing the varying width of overcurrent characteristic of the secondary DC voltage, and controlling the overcurrent characteristic of the voltage. CONSTITUTION:A ringing choke converter (RCC) 1 rectifies an input AC voltage by a rectifier to the primary DC voltage, which is again converted to an AC voltage by a transistor Tr1. This is produced from the secondary side of a transformer T1, rectified and smoothed to obtain the secondary DC voltage V0. The voltage V0 is fed back through a photocoupler PC1 to a constant-voltage circuit 2, and stabilized. In this case, a resistor R7 and Zener diodes DZ1, DZ2 of series connection are connected in parallel with the series connection of a diode D1 and a capacitor C4 of the RCC circuit 1. Thus, the influence of the variation in the input AC voltage to the bias voltage Vbe of a transistor Tr2 is eliminated to obtain the overcurrent characteristic of the secondary DC voltage V0 having stable drooping characteristic. |
