SWITCH MODE POWER SUPPLY CONTROLLERS

摘要

This invention relates to SMPS controllers employing primary side sensing to detect a point of zero magnetic flux, at which the output voltage of the SMPS may be sampled accurately on the primary side. We describe a switch mode power supply (SMPS) controller for regulating the output voltage of an SMPS is response to a feedback signal from an auxilliary winding of a magnetic energy storage device forming part of an output circuit of the SMPS, the SMPS controller comprising: a reference level input to receive an output reference level signal; an input to receive said feedback signal, said feedback signal being responsive to a voltage on said auxilliary winding of said magnetic energy storage device; an integrator to integrate a difference between said feedback signal and a first fixed reference level signal; a first comparator to compare an output of said integrator with a second fixed reference level signal and to provide an output responsive to said comparison for regulating said SMPS output voltage.