Circuit-Specific and Technology-Independent Criterion for Selection of Power MOSFETs That Minimize Energy Dissipation

We investigate the impact of power MOSFET channel width on the power efficiency of a switch-mode power supply. With this analysis, we derive a circuit-specific criterion that minimizes the power dissipated by a power MOSFET, which is based on the ratio between on resistance and output capacitance of the MOSFET and is independent of its technological parameters. The effect of channel width on the power dissipation is illustrated by simulation-based analysis, which also provide an example of a published non-optimum selection of a power MOSFET and demonstrate the advantage of the newly proposed method for MOSFET selection.