Multiphase synchronous buck converter with improved power loss balancing

摘要

A multi-phase synchronous buck converter having plural single phase synchronous buck converter stages, connected together to provide an output current to a load. A sensing circuit in each converter stage includes a variable gain current sense amplifier that determines the current through the shunt MOSFET to generate an output signal representative of the output current provided by that converter stage. The gains of the current sense amplifiers in each converter stage are preset such that the output signals from all the amplifiers are substantially equal, thereby balancing the power loss in all the converter stages by adjustment of the output currents using varying current sense gains to compensate for variations in the R_DS-ON of the shunt MOSFETS.