LOW-COST SOFT SWITCHING IN PARALLELED SWITCH ASSEMBLIES

摘要

An apparatus and method for reducing power loss due to switching of a switch mode power converter includes a power converter having a plurality of switch assemblies (14, 16, 214, 216), each connected in parallel through an inductor (20, 26, 220, 226) to a common output node (30) and a diode (22, 28, 222, 228) connected to a second common output node (34), and a switch controller (12, 212, 412, 612, 812) for activating and deactivating the plurality of switch assemblies (14, 16, 214, 216) during successive switching cycles. The controller activates and deactivates each switch assembly (14, 16, 214, 216) one time during each switching cycle and activates one subset of switch assemblies before activating the remaining switch assemblies. The switch controller provides enable signals to commute the subset of switch assemblies (14, 16, 214, 216) among the plurality of switch assemblies to be activated before the remaining switch assemblies. The switch controller includes a modulator (42) for modulating a clock signal (48) and demand signal (52), and at least one delay circuit (44) for providing a signal which is delayed in time relative to the modulated signal.