Patent ID: 7307390

Claim:
A primary side, constant output voltage Pulse Width Modulation (PWM) controller system for a switching regulator with a transformer having at least a primary winding and a secondary winding, the system comprising: a timing generator configured to generate a sample timing signal based on a feedback signal, the sample timing signal being operable for controlling sampling in either a discontinuous current mode or a continuous current mode of operation; a first sample-and-hold circuit operable for sampling the feedback signal, the first sample-and-hold circuit being configured with a control input that receives the sample timing signal and wherein the control input is operable for controlling the sampling; an error amplifier that receives a reference signal and the feedback signal and that outputs a signal based on the difference there between, wherein the reference signal sets the output voltage level of the switching regulator; a comparator that is configured to output a comparison between the error amplifier output and at least one ramp signal; an oscillator; a PWM controller module that outputs a PWM switching regulator control signal based on an oscillator output and the comparator output; and a gate drive module that receives the PWM switching regulator control signal and generates a corresponding gate drive signal operable for turning on or off a switched power output device of the switching regulator.