Synthetic ripple regulator with frequency control

An electronic device, comprising:

• a synthetic ripple regulator which converts an input voltage to a regulated output voltage and which includes frequency control based on a fixed frequency reference clock, wherein said synthetic ripple regulator comprises:
• an error network providing an error signal indicative of relative error of the output voltage;
• a ripple detector which provides a ramp control signal based on said input and output voltages and a pulse control signal;
• a combiner which adjusts said ramp control signal based on a frequency compensation signal to provide an adjusted ramp control signal;
• a ripple generator which develops a ripple control signal based on said adjusted ramp control signal;
• a comparator network which develops said pulse control signal to control switching based on said error signal and said ripple control signal at a frequency that varies in response to load transients;
• and
• a phase comparator which compares said pulse control signal with said reference clock and which provides said frequency compensation signal indicative thereof to control steady-state operating frequency of said synthetic ripple regulator by adjusting said ramp control signal to adjust said frequency of said pulse control signal towards said fixed frequency of said reference clock.

A method of controlling steady-state switching frequency of a synthetic ripple regulator based on a fixed frequency reference clock, wherein the synthetic ripple regulator converts an input voltage to a regulated output voltage, the method comprising:

• determining an error of the output voltage and providing a compensation signal indicative thereof;
• developing a window signal with upper and lower limits using the compensation signal;
• generating a ramp signal based on a difference between the input and output voltages when a pulse control signal is asserted high and based on the output voltage when the pulse control signal is asserted low;
• providing a frequency compensation value based on comparing the pulse control signal and the reference clock;
• adjusting the ramp signal based on the frequency compensation value and providing an adjusted ramp signal to adjust a frequency of the pulse control signal towards the fixed frequency of the reference clock;
• converting the adjusted ramp signal to a ripple signal;
• and
• comparing the ripple signal and the window signal and providing the pulse control signal indicative thereof at a frequency that varies in response to load transients.