CALCULATORS / POWER CONVERSION AND SWITCHING

Switching-inductor current ripple calculator

Ideal CCM buck inductor ripple at supplied switching frequency.

power-electronics-inductor-ripple.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

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

Scenario	duty	rippleA
	0.5	0.6
	0.625	0.45

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.

ripple budget0.60 A✓ passes

BASELINE INPUTS

input24 Voutput12 Vinductance100 uHfrequency100000 Hz

CALCULATED

duty0.5

ripple0.6 A

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Switching-inductor current ripple
# Scope: Ideal CCM buck inductor ripple at supplied switching frequency.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

input = 24 V
output = 12 V
inductance = 100 uH
frequency = 100000 Hz

duty := output/input
ripple := (input-output)*duty/(inductance*frequency) [A]

check ripple budget: ripple <= 1 A

scenario alternative: input = 19.2 V

Calculated from your source · not saved

Baseline · Baseline

ripple budget0.60 A ✓ passes

alternative · alternative

ripple budget0.45 A ✓ 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.

duty: duty = output/input
ripple: ripple = (input-output)*duty/(inductance*frequency) [A]

Original worked example

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

Given

input: 24 V
output: 12 V
inductance: 100 uH
frequency: 100000 Hz

Calculated

duty: 0.5
ripple: 0.6 A

Assumptions and limits

Ideal CCM buck inductor ripple at supplied switching frequency.

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: Switching-inductor current ripple. Inputs: applied volt-seconds; inductance; switching period. Outputs: ripple; peak and RMS currents. 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: applied volt-seconds, inductance, switching period
Outputs: ripple, peak and RMS currents
Modes: calculate, compare, sweep
Drawing: Switching waveforms and loss plots

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