Control study of a 500 kHz, 250 W DC-DC converter

Circuit waveforms and control strategies for a multiple-output pseudoresonant DC-DC converter described by R.A. Fisher et al. (1988) have been studied through multilevel simulation using a mix of behavioral and device models. Circuit waveforms show the expected pseudoresonant switching. Voltage-mode and current-mode control are both found to be feasible. Current-mode control, when properly implemented, has the advantage of reducing the inherent second-order system response to a first-order one. The converter's potential instability can be eliminated with the addition of a stabilizing ramp on the control current. Regulating the current in the transformer primary gives behavior similar to voltage-mode control.<<ETX>>