Control method and circuit to provide voltage and current regulation for multiphase DC/DC converters

摘要

A multiphase DC/DC converter with voltage-mode hysteretic control and instantaneous current sharing functionality method and circuit. The disclosed method and circuit provides independent output voltage regulation and phases current regulation for the converter in two separate loops; one of which is concerned with voltage regulation preferably hysteretic regulation and the other which is concerned with phase current regulation. In one embodiment, each phase in the DC/DC converter is driven by a frequency divided signal derived directly from the output voltage ripple so that each phase has a switching frequency equal to the output voltage ripple frequency divided by the number of paralleled phase. In another embodiment, only the phase that carries the smallest current among a set of phases will be turned ON in each switching cycle to supply power to the output, avoiding multiple switching. Current sharing and regulation is achieved without shortening the ON time and with no multiple switching in any cycle.