Automatic gating control of lowest voltage switching for boundary mode buck converters

This study presents an integrated circuit approach, lowest voltage switching (LVS), for boundary mode buck converters. This technique automatically locates the optimum timing of turning on the power MOS at the lowest drain-to-source voltage by compensating the circuit delay. Switching loss and noise can be reduced. No additional external components or timing calculation circuits are required. It can also be applied to other switching circuits, such as boost and buck-boost. A boundary mode buck converter with V_IN of 5 V and V_OUT of 1.81 V is designed and fabricated. At 1.35 MHz operation, the measured conversion efficiency of the buck converter with the presented LVS control scheme is 9 higher than that without LVS.