Systems and Methods of CCM Primary-Side Regulation

摘要

Example embodiments of the systems and methods of CCM primary-side regulation disclosed herein subtract an estimate of the secondary IR drop from each output voltage sample. This allows a fixed sample instant to be set (with regard to the beginning of the off or flyback interval), and removes the need to hunt for or adjust to an optimum sample instant, or one with minimum IR drop error. The estimate of the IR drop may be adjusted on a cycle-by-cycle basis, based on the commanded primary peak current, knowing that the peak secondary current will be directly proportional by the turns ratio of the transformer. For improved accuracy, an adjustment may be made for the decay of secondary current during the delay to the sample instant, if the inductance value is known.

主权项

1. A system comprising:
a voltage converter comprising a flyback transformer with at least a primary winding, a secondary winding and a dedicated bias/sense winding; a primary side switch; and a flyback controller configured to sample an output voltage at a fixed time during a secondary decay period and modulate the primary switch based on an adjustment to the sampled output voltage.