To maximize power efficiency, dead time between “on” times of a synchronous rectifier (“SR”) MOSFET switch and a main switch for CCM operation in particular in isolated and non-isolated self-driven synchronous DC-DC converters needs to be optimized. To accomplish that objective, the latest conduction time t of a body diode of the SR MOSFET following conduction thereof is determined, compared with a selected fixed optimum period T1, and incrementally or decrementally adjusted in a subsequent switching cycle while t is unequal to T1, depending on whether t is shorter or longer than T1, so that t eventually is made substantially equal to T1 in length. This process is to be repeated continuously.