Patent ID: 7532082

Claim:
A synchronization circuit for synchronizing at least two self-oscillating PWM modulators, each outputting a respective pulse-width-modulated output signal comprising signal pulses with signal pulse centers; said synchronizing circuit shifting the timings of said signal pulses relative to one another such that said signal pulse centers are in sync; wherein each of said self-oscillating PWM modulators comprises: a signal input for receiving an analogue input signal; an input signal filter producing a filtered difference signal by filtering a difference signal between said analogue input signal and a feedback signal; a comparator for generating a comparator output signal by comparing said filtered difference signal with a reference voltage; a delay circuit for generating a delayed comparator output signal by delaying said comparator output signal on the basis of a synchronization control signal; a power stage amplifying for generating an amplified comparator output signal by amplifying said delayed comparator output signal; a feedback filter for generating a feedback signal for said input signal filter by filtering said amplified comparator output signal; and a signal output outputting said amplified comparator output signal as said respective pulse-width-modulated output signals of the relevant of said PWM modulators.