| 摘要 |
A switching power supply is provided which carries out output control without feeding back output voltage and output current to the primary side of an output transformer. A switching power supply comprises an output transformer (3) having a primary winding coupled to rectified ripple voltage; input voltage detection means (4) connected in parallel with the primary of the output transformer (3) and adapted to compare the ripple voltage with a threshold to produce a switching disable signal or a switching enable signal depending on the result of comparison; and switching means (5) connected in series with the primary of the output transformer (3) and connected with the input voltage detection means (4) so that it may start switching in response to a switching enable signal and stop switching in response to a switching disable signal. |
