MOSFET Gate Drive Power Calculator
Calculate MOSFET gate energy, per-device and total gate-drive power, driver input power, and average gate current from total gate charge, drive voltage, switching frequency, and device count.
Use the estimate when selecting gate-driver supply capacity, decoupling, package thermal margin, and control-stage power budgets in switching converters and motor drives.
Engineering tool
MOSFET Gate Drive Power Calculator
Calculate gate energy, per-device and total gate-drive power, driver input power, and average gate current.
Use Qg at the relevant gate voltage, drain voltage, and load current.
Full gate-voltage swing supplied by the driver.
Complete gate charge-discharge cycles per second.
Number of identical gates driven at this frequency.
Estimated conversion efficiency from driver supply input to gate energy.
Result console
- Gate energy per cycle
- 0.5µJ
- Gate-drive power per MOSFET
- 50mW
- Total gate-drive power
- 50mW
- Driver input power
- 55.555556mW
- Average gate current
- 5mA
Engineering recommendation
Low Driver Load
The average gate-drive load is modest, but confirm driver peak current, source and sink asymmetry, dead time, decoupling, and worst-case Qg from the datasheet.
Formula reference
MOSFET Gate Drive Power Formulas
The first-order model assumes the full specified gate charge is transferred during every switching cycle for each MOSFET.
Gate energy per cycle: Eg = Qg × VGSGate-drive power per MOSFET: Pgate,device = Eg × fswTotal gate-drive power: Pgate,total = Pgate,device × NDriver input power: Pdriver,input = Pgate,total / efficiencyAverage gate current: Iavg = Qg × fsw × NVariable definitions
- Qg
- total gate charge
- VGS
- gate-drive voltage swing
- fsw
- switching frequency
- N
- number of MOSFETs
- efficiency
- driver power-transfer efficiency as a decimal
Worked Example
Qg = 50 nC, VGS = 10 V, fsw = 100 kHz, N = 1, and driver efficiency = 90%.
Eg = 50 nC × 10 V = 0.5 µJ per cycle
Pgate,device = 0.5 µJ × 100 kHz = 50 mW
Pgate,total = 50 mW × 1 = 50 mW
Pdriver,input = 50 mW / 0.9 ≈ 55.6 mW
Iavg = 50 nC × 100 kHz × 1 = 5 mA
Engineering Notes
Frequency scaling
Gate-drive power increases linearly with switching frequency.
Gate charge
A larger total gate charge requires more driver energy during every cycle.
Drive voltage
Higher gate voltage increases gate-drive energy and average power.
Multiple devices
Multiple MOSFETs multiply total gate charge, current demand, and driver load.
High-frequency design
Gate-drive power is often modest but can matter in high-frequency converters and multi-phase systems.
Support reference
FAQ
How do you calculate MOSFET gate drive power?
Multiply total gate charge by gate-drive voltage to find energy per cycle, then multiply by switching frequency and the number of MOSFETs: Pgate = Qg × VGS × fsw × N.
What is gate charge Qg?
Total gate charge is the electrical charge the driver must source and sink to move the MOSFET gate through a switching cycle under specified voltage and current conditions.
Why does switching frequency affect gate drive power?
The driver transfers gate energy during every switching cycle, so doubling switching frequency doubles the average gate-drive power for the same Qg and VGS.
Is gate drive power the same as switching loss?
No. Gate-drive power is consumed by charging and discharging the gate. MOSFET switching loss is mainly dissipated in the MOSFET during drain voltage and current overlap, although both depend on switching behavior.
How do multiple MOSFETs affect gate drive power?
For identical devices switching together, total gate charge, average gate current, and gate-drive power increase approximately in direct proportion to the number of MOSFETs.
Documentation
Related Engineering Guides
Design notes, guides, and engineering articles linked to this tool.
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