Multivariable analysis of vr controllers with load line regulation and phase current balancing

The multivariable complexity of multiphase buck voltage regulators, is examined, including multi-input-multi-output models and multiple control objectives. Voltage regulation, load line regulation and phase current balancing are found to be competing control objectives. Decoupling control frameworks are proposed that resolve the multivariable conflict and simplify the controller design. Strategies for output impedance shaping are proposed. Simple current balancing control is demonstrated, which is also extended to provide novel phase shedding and asymmetrical current sharing control. This paper provides a complete voltage regulator control solution.