Adjustable Reset Voltage for a Forward Converter
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
This article describes a circuit arrangement which uses a buck-boost converter to discharge the reset capacitor of a forward converter into the bulk input voltage. In some existing forward converter such as shown in Figs. 1a and 1b, the use of 800 V transistors is required which permits a maximum duty cycle of 0.5. An unequal number of turns in the primary and reset windings will improve one at the expense of the other. If NR = NP, then the voltage that Q1 must withstand is VQ = 2VB. The maximum duty cycle is limited by the reset time of the transformer. (Image Omitted) For the standard forward converter, because VR = VP, the maximum allowed duty cycle is 0.5.