Table 9-1 shows a typical set of performance requirements for a high-voltage flyback converter capable of delivering 15 V output from a 40 V to 1000 V DC input. From 125 V to 1000 V input, the converter can deliver 40 W. From 40 V to 125 V input, the converter is derated to deliver 20 W. To minimize the transformer size and reduce losses, the power stage is designed such that it operates in discontinuous conduction mode (DCM) at high input voltage and very near transition mode at low input voltage. In DCM mode (i.e. relatively high input voltage) the magnetizing current is reset to zero before the start of the next PWM cycle. Compared to continuous conduction mode (CCM), DCM provides the advantage of very low turn-on switching losses, even at high V_IN, because the current always starts from 0A. Also, in DCM mode, the output rectifier current decays to zero before the next switching event. Therefore, DCM eliminates the reverse recovery losses of the output rectifier, unlike CCM.

The peak power of the converter is designed to support 48 W, 120 % higher than the nominal 40 W.