Dynamic current sharing analyses for multiphase buck VRs

For high-control-bandwidth multiphase buck voltage regulators, this paper addresses the issue of dynamic current sharing among interleaved phases, especially under repetitive high-frequency load transients. The beat-frequency oscillation phenomenon of phase currents is identified and explained by a proposed small-signal model including the sideband information. To reduce the sideband frequency component while not impacting the control loop's phase margin, the notch filter solution is proposed. Dynamic current sharing improvements with this method are proven by the experimental results for different control structures.