Input voltage ripple based sensorless current sharing auto-tuning controller for multiphase DC-DC converters

Current sharing is commonly used in multiphase converters in order to ensure equal current distribution between converter phases. Conventional current sharing control schemes typically require sensing the phases´ currents, which results in increased complexity, size and cost in addition to issues associated with sensing inaccuracies. In this paper, a sensorless current sharing control scheme is proposed in order to achieve equal current sharing among the phases without the need for current sensing and calibration circuitries. The proposed controller achieves equal current sharing based on auto-tuning the phases´ duty cycle values to minimize the differences between the input voltage ripple values within a switching cycle of each phase. Simulation results obtained from a two-phase synchronous buck converter are presented to verify the operation and advantages of the proposed concept.