A DC-DC converter and method of improving the efficiency of a DC-DC converter at low load current levels using pulse skipping modulation (PSM) with controllable burst duration NT.sub.clk, where T.sub.clk is the clock cycle interval. As the average load current increases, the time between bursts decreases so that average inductor current matches the load current. The burst duration is kept around NT.sub.clk by controlling the duty cycle of the output switches. The higher the load current, the higher is the duty cycle of the output switches. No current sensing is needed. The optimum burst duration for best efficiency curve is a function of the load capacitor.