Input Voltage Ripple-Based Sensorless Current Sharing Autotuning Controller for Multiphase DC–DC Converters.

Current sharing controller/functionality is commonly utilized for multiphase converters to achieve current balancing between converter phases. Conventional current sharing control schemes generally require sensing the current of each phase, leading to increased size and cost in addition to issues associated with current sensing inaccuracies. A sensorless current sharing control scheme is proposed in this paper that utilizes the difference between the input capacitor voltage ripple values to indicate the phases' current distribution status. The duty-cycle value of each phase is autotuned in a way to minimize the difference between the input capacitor voltage ripple values based on a single voltage sensing point, which results in equal current sharing with no need for current sensing. In addition, the input capacitor voltage ripple sensing does not need to be very accurate, and the sinusoidal frequency component of interest of the ripple is obtained by using a low-cost bandpass filter for improved ripple sensing resolution and noise immunity. Experimental results obtained from a digitally controlled two-phase synchronous buck converter prototype are presented to validate the feasibility of the proposed concept. [ABSTRACT FROM PUBLISHER]