A multiphase synthetic ripple voltage generator for a multiphase DC-DC regulator
including a master clock circuit that generates a master clock signal, sequence
logic and a ripple regulator for each phase. The DC-DC regulator includes multiple
switching circuits, each responsive to a corresponding PWM signal to switch input
voltages via a phase node through an output inductor to develop an output voltage.
The sequence logic sets each PWM signal in sequential order based on the master
clock signal. Each ripple generator includes a transconductance amplifier, a ripple
capacitor and a comparator. The transconductance amplifier has an input coupled
to a corresponding output inductor and an output coupled to a corresponding ripple
capacitor. The comparator has a first input coupled to the ripple capacitor, a
second input receiving an error voltage, and an output coupled to the sequence
logic for resetting a corresponding PWM signal.