This invention relates to SMPS controllers employing primary side sensing. We describe a system for identifying a knee point in a sensing waveform, at which the output voltage of the SMPS may be sampled accurately on the primary side. The system identifies the knee point by fitting a tangent to a portion...http://www.google.com/patents/US20090237960?utm_source=gb-gplus-sharePatent US20090237960 - SWITCH MODE POWER SUPPLY CONTROLLERS
