The autonomy of battery-operated electronic systems directly depends on the energy conversion efficiency from the battery to the lower voltage levels required by nowadays CMOS technologies. One of the major contributions for power losses in buck dc-dc converters is explained and analyzed. The work presented in this paper focuses on optimizing buck converter efficiency (synchronous rectification) by minimizing body-diode conduction losses. A new control technique, and a drive system that regulates the dead-time to a minimum value of 2 ns, are presented. Converter losses decrease by 19 % to 32 % when compared to the fixed dead-time solution.