| 摘要 |
A switching power supply, e.g. for a printing apparatus, includes a transformer T9 for generating a first output voltage by a first secondary winding 12, and a superimposing voltage by a second secondary winding 12a, and a driver IC1, Q1. The first output voltage and the superimposing voltage are rectified and smoothed by respective circuits D2, C4 and D91, C91 and the rectified and smoothed superimposing voltage Î Vs is added to the rectified and smoothed first output voltage Vo1 to produce a second output voltage Vo2. The first and second output voltages are fed back respectively by DC coupling, and adjusted by first and second feedback factors, and the adjusted feedback components are applied to the driver for PWM control. |
