Current Sharing in Multiphase Converters Using Temperature Equalization

Multi-phase converters offer excellent performance advantages in transient response and efficiency. A case in point is the core converter for personal computers. These advantages can only be fully achieved if we guarantee load current sharing between all the phases of the design. This paper offers a novel approach in achieving this goal while at the same time guaranteeing another very important parameter - namely, equalization of case temperature of the switching MOSFETs. The approach taken here is to measure the temperature of the switching devices in each phase and regulate the switching current per phase so as to maintain the same temperature in all phases. Since both the conduction and dynamic losses are directly proportional to the switching current, changing the phase current amplitude higher or lower will increase or decrease the phase temperature allowing the control loop to equalize the phase temperature and current among all phases