Negative lock loop and control method for a flyback voltage converter

摘要

A flyback voltage converter includes a transformer having a primary winding and a secondary winding, a switch serially connected to the primary winding for being switched to produce a current in the secondary winding, and a negative lock loop to adjust the peak value of the current in the secondary winding according to a current conduction time during which the current in the secondary winding is higher than a current threshold, such that the peak value of the current in the secondary winding will be in inverse proportion to the time.