Adaptive reactivation of phases deactivated by phase-shedding in multi-phase voltage regulators

摘要

In a multi-phase power supply voltage regulator functioning at a nominal switching frequency, one or more phases are kept off for optimizing energy efficiency at relatively low load conditions. Reactivation of stand-by phases in response to a load increase transient is made more efficiently by exploiting information already present in the output voltage control loop. The technique comprises a) deriving from the control loop information on the equivalent nominal switching frequency given by the product of the nominal switching frequency by the number of active phases; b) updating at every beat of a clock signal the instantaneous value of the equivalent switching frequency; c) determining the band of equivalent switching frequency values to which the instantaneous value belongs; d) logically combining the equivalent switching frequency information with a determined band of output current level, for switching on one or more stand-by phases in response to a load increase transient.