US Patent 7906868 Fine tuned multiple output converter

A secondary side voltage regulation scheme applied to a multiple output flyback converter. The output with the highest error voltage is selected to control the primary switch. The remaining outputs are regulated by varying the length of time that current is allowed to flow into each output by controlling the on time of a switch connected in series with each of the outputs. The switching of the windings is achieved using a single N channel MOSFET for each output. Regulation of the outputs is performed using leading edge modulation. The body diode of the output MOSFET switches are held off during the start of the commutation period by the use of an active clamp on the primary side.