Side-by-side
| Aspect | MOSFET | IGBT |
|---|---|---|
| Structure | Voltage-controlled FET | FET gate drives BJT output |
| V_drive | 10–15 V gate (standard) | 15–20 V gate |
| On-state drop | R_DS(on) · I (low at low V, rises with V) | V_CE(sat) ≈ 1–2 V (roughly constant) |
| Switching speed | Fastest (ns) | Slower (100 ns – µs) — has tail current |
| Typical V rating | 20–1 000 V | 600–6 500 V |
| Typical I rating | 0.1 A – 400 A | 5 A – 3 000 A |
| Switching losses | Low (square turn-off) | Higher (tail current at turn-off) |
| Conduction losses | Low at low current / V | Low at high current / V |
| Temp coefficient | Positive (parallels well) | Negative at low I — parallel with caution |
Rule of thumb
| < 250 V | MOSFET — lower R_DS(on), faster |
|---|---|
| 250–600 V | Modern Si or SiC MOSFETs take over traditional IGBT territory |
| > 600 V, high power | IGBT — lower conduction loss at high V/I |
| > 20 kHz switching | MOSFET (Si or SiC) — IGBT tail current dominates |
| Motor drives (kW) | IGBT common; SiC MOSFETs displacing at higher efficiency |
Notes
- SiC (silicon carbide) and GaN (gallium nitride) MOSFETs extend the MOSFET sweet spot to higher voltage and frequency.
- IGBTs have a tail current at turn-off — keep switching frequency below ~20 kHz to limit loss.
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