Modeling of unbalanced multiphase buck converters with applications to voltage regulator module control

Multiple parallel-input parallel-output low-output voltage converters serve high-current high-slew rate loads, often using current mode control to achieve tight output voltage regulation. One way to enhance slew rate performance is to combine unbalanced phases: a low inductance converter in parallel with one or more conventional phases can deliver fast slews without altering low-frequency performance. An unbalanced combination is facilitated by combining conventional current-mode controls with sensorless current mode (SCM) controls; The dynamic properties resulting from using equal and unequal filter inductances for parallel converters are investigated for a 12 V to 1.5 V 100 A VRM.