CALCULATORS / POWER CONVERSION AND SWITCHING

MOSFET gate-drive sizing calculator

Gate charge average current and drive power; charge supplied at actual operating point.

power-electronics-gate-drive.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	averageCurrentA	powerW	peakApproximationA
	0.003	0.03	0.3
	0.0024	0.024	0.24

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

drive power budget0.03 W✓ passes

BASELINE INPUTS

charge30 nCdriveVoltage10 Vfrequency100000 HzswitchTime100 ns

CALCULATED

averageCurrent0.003 A

power0.03 W

peakApproximation0.3 A

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# MOSFET gate-drive sizing
# Scope: Gate charge average current and drive power; charge supplied at actual operating point.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

charge = 30 nC
driveVoltage = 10 V
frequency = 100000 Hz
switchTime = 100 ns

averageCurrent := charge*frequency [A]
power := charge*driveVoltage*frequency [W]
peakApproximation := charge/switchTime [A]

check drive power budget: power <= 0.1 W

scenario alternative: charge = 24 nC

Calculated from your source · not saved

Baseline · Baseline

drive power budget0.03 W ✓ passes

alternative · alternative

drive power budget0.02 W ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

average current: averageCurrent = charge*frequency [A]
power: power = charge*driveVoltage*frequency [W]
peak approximation: peakApproximation = charge/switchTime [A]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

charge: 30 nC
drive voltage: 10 V
frequency: 100000 Hz
switch time: 100 ns

Calculated

average current: 0.003 A
power: 0.03 W
peak approximation: 0.3 A

Assumptions and limits

Gate charge average current and drive power; charge supplied at actual operating point.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: MOSFET gate-drive sizing. Inputs: gate charge; frequency; desired switching time; voltage. Outputs: driver current; gate power; resistance screening. Model scope: First-order switching models and explicit nonidealities. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: gate charge, frequency, desired switching time, voltage
Outputs: driver current, gate power, resistance screening
Modes: calculate, compare, sweep
Drawing: Switching waveforms and loss plots

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS