The input terminal I/P is further electrically connected to a power source 13 to receive electric power from the power source 13. The first output terminal O/P1 and the second output terminal O/P2 are further electrically connected to a load 14 to transmit electric power to the load 14.

When the switch 12 is turned on, the power source 13 may provide a primary current flowing through a series circuit including the primary winding Wp and the switch 12 connected to the ground. Further, the second capacitor C2 may discharge to output a current Ic2 to charge the first capacitor C1 through the first inductor L1 and the third diode D3.

When the switch 12 is turned off, the first capacitor C1 may discharge. Further, the second diode D2 and the second capacitor C2 are used to transfer energy from a leakage inductance between the primary winding Wp and the second winding Ws to a capacitor, clamping a voltage spike. The clamping winding Wc is employed to allow for a direct current (DC) offset compared to the primary winding Wp. The first inductor L1 discharges the capacitor, but allowing energy to be returned to the power source 13 instead of being dissipated.

Therefore, at the moment that the switch 12 is turned off, the first capacitor C1 conducting through the first diode D1 will slow the primary winding Wp transition, reducing Electromagnetic interference (EMI). The first capacitor C1 and the first diode D1 do little to limit the voltage spike.