Efficiency improvement for forward DC-DC converter employing synchronous rectifier

An LC snubber combined with a single-ended forward converter in its primary, as a basic investigation, is proposed in this paper to improve further the efficiency of the DC-DC converter employing a synchronous rectifier. It is known that the synchronous rectifier is more efficient than traditional rectifiers. Moreover, by using this nondissipative LC turn-off snubber on converters employing synchronous rectifiers, the turn-off surge can be suppressed, the transformer can be reset, and energy recovery can be achieved. Accordingly, the efficiency of this converter will be further uplifted. For the proposed forward converter with 40 W output, 91% efficiency at 3.3 V and 4 A output is obtained. In this paper, the circuit operation of this converter is verified by simulating the steady state response of this circuit, and its design criteria are also discussed.