Patent ID: 7408793

Claim:
In a DC-DC converter having a rectifying diode, an input circuit coupled to the diode, an output circuit coupled to the diode, and a snubber circuit connected in parallel with the diodes, the snubber circuit having a capacitor and being tuned to damp resonant ringing in the output circuit upon abrupt current changes through the diode; the improvement comprising a controlled switching element connected in series with the capacitor and responsive to a control signal to complete and interrupt a current path to the capacitor, and a control signal source connected with the controlled switching element for applying to the controlled switching element a control signal timed to interrupt the current path to the capacitor subsequent to damping by the snubber circuit and prior to discharge of the capacitor and to complete the current path to the capacitor during a transition period when the abrupt current change occurs, at or before the onset of the ringing.