Common-Source Active Clamped Complex Type Converter

Abstract

An active clamped circuit is widely used in switching converters for transformer reset, surge suppression, and soft switching. However, Two MOSFET switchies are driven by the different gland level in which the conventional active clamped circuit, By adding an auxiliary winding to the transformer, proposed converter is a common-source type that is direct connection of sources of the two MOSFET switches. As a result, the pulse transformer becomes unnessary, and the drive circuit is simplified. Fig.1 shows the common-source active clamped complex type converter. Fig. 2, 3 show the observed waveforms of main switch Q1 and auxiliary switch Q2 at 12V/6A. The turn-off voltage surge of both switchs suppressed. Fig.4 shows the turn-n waveforms of main switch Q1. The current is rising, after the voltage becomes the zero, and the ZVS operation can be confirmed. Fig.5 shows the efficiency characteristics of world wide input range. The highest efficiency 92.7% is obtained at 48V ratings input range.It is verified that proposed converter corresponds to the world wide input range, and the ZVS operation is performed on main switch and auxiliary switch.