1results about How to "Avoid dead time" patented technology

The application discloses a working mode detection method and circuit of an active clamp flyback converter, a main control chip, samples a drain end voltage VDS of a main power tube QL in a current period, detects a first voltage drop time of the main power tube QL after the main power tube QL is turned off, and determines the working mode of the current period of the active clamp flyback converter by judging the sequence of the first voltage drop time and a clamp tube driving time. Furthermore, based on the working mode determination result, the dead time of the active clamp flyback converter is accurately adjusted to be suitable for the detected working mode, the problem of mismatching between the dead time and the working mode is avoided, the main power tube QL of the active clamp flyback converter can keep realizing soft switching in a full load range, the switching loss of the active clamp flyback converter is greatly reduced, and the efficiency of the converter is improved.