Patent ID: 7499295

Claim:
A method of regulating the output of a switch mode power supply (SMPS) operating in a discontinuous conduction mode, the method comprising: monitoring a feedback signal from at least one of a primary winding and an auxiliary winding of a magnetic energy storage device forming part of an output circuit of said SMPS, said feedback signal including a decaying portion representing a decaying voltage in said output circuit of said SMPS followed by an oscillatory portion when substantially no energy is being transferred to said SMPS output; comparing said feedback signal with a reference dependent on a target output voltage to identifying a point in said decaying portion of said feedback signal defined by said target output voltage for said SMPS; resetting an integrator at said identified point; integrating said feedback signal using said integrator starting from said identified point; and regulating said SMPS output responsive to a comparison, at a defined point in said oscillatory portion of said feedback signal, of a result of said integrating with a second reference value.