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MOSFET Selection

Engineering reference on MOSFET Selection for wireless power system design, integration, and deployment.

6 minArticle 06/50Power Electronics

MOSFET Selection — educational diagram — Fig.: Educational diagram for “MOSFET Selection”.

MOSFET selection balances conduction loss (I²RDS(on)), switching loss (Qg, Qoss, trr of body diode), and voltage rating for ringing and misalignment overshoot. In a charging dock inverter, the same part may see soft-switched operation at nominal load and hard switching during fault or startup.

Industrial wireless power favors parts with known avalanche behavior, consistent parametrics across batches, and availability for multi-year fleet spares.

01Selection criteria

VDSS with margin above worst-case spike including layout overshoot.
RDS(on) at operating junction temperature, not 25 °C datasheet.
Gate charge versus driver capability — weak drive erases fast FET advantage.
Body diode reverse recovery if it conducts during dead time or hard commutation.

MOSFET Selection — supporting diagram — Fig.: Supporting illustration for “MOSFET Selection”.

02Si vs wide bandgap

Silicon superjunction MOSFETs remain cost-effective at moderate frequency. SiC and GaN extend frequency and efficiency when magnetics and layout can support faster edges. The winning device is the one that minimizes total loss at your frequency, current, and cooling budget — not the newest technology label.

03Validation

Double-pulse testing on the actual PCB, not an evaluation board.
Temperature cycling under dock enclosure limits.
Spares and second-source policy before fleet lock-in.