Calculation of Power Loss in Output Diode of a Flyback Switching DC-DC Converter

Based on the mathematical model of flyback switching DC-DC converter in the continuous current mode and the simulation model under heavy loads, this paper presents a study of the steady-state power loss in the output diode, including the loss calculation models under three operational modes (voltage control, under-voltage, and over-current modes), the relations of the diode loss versus the input and output voltages, and a comparison of the losses under different modes. By the heavy load simulation model, the effects of time delay on the diode loss are also investigated. Finally, the proposed models are applied to calculate the power losses of output diode of an existing flyback switching DC-DC converter