Forward Converter
The reset winding (left) dumps the stored energy in the primary winding back to the input source. If this did not happen, the voltage across the primary would attempt to rise to infinity and blow the switching transistor. Magnetizing flux would also buildup and saturate the core.
Initial State
Step 1 – Close the switch.
Step 2 – Open the switch.
Two Transistor Forward Converter
http://www.onsemi.com/pub/Collateral/AND8039-D.PDF
http://www.fairchildsemi.com/an/AN/AN-4134.pdf
http://www.national.com/appinfo/power/files/f22.pdf
http://www.national.com/an/AN/AN-776.pdf
http://www.powerint.com/PDFFiles/an31.pdf
http://www.eetasia.com/ARTICLES/2004DEC/A/2004DEC01_MPR_AN03.PDF
http://www.coremaster.com/appnotes/an106.pdf
http://www.coremaster.com/appnotes/an107.pdf
http://www.coilws.com/AppNotes/FTT%20AN02.pdf
http://alpha400.ee.unsw.edu.au/elec4240/Lecture%2016.pdf