Sensorless Current Sharing in Digitally Controlled Two-Phase Buck DC-DC Converters

Abstract

This paper describes a current sharing technique for digitally controlled two-phase buck DC-DC converters where pulse width and resistance mismatches are digitally compensated to achieve approximately equal current sharing without sensing currents. Effects of various non-idealities on the current sharing performance are discussed and corresponding mitigation techniques are presented. An extension to converters with more than two phases is discussed. Experimental results are shown for a two-phase synchronous buck converter with 6V input voltage, and 1.3 V, 0 - 20 A output.