Boost Converter Duty Cycle

Enter values to compute duty cycle (D), output voltage (Vout), or input voltage (Vin) using the ideal boost relationship. Includes an optional efficiency estimate and Show Work.

How to Use

  1. Pick a solve mode: Duty Cycle, Vout, or Vin.
  2. Enter the required values (typically Vin + Vout).
  3. (Optional) Enter efficiency to estimate non-ideal output.
  4. Open “Show Work” to see formulas and steps.
Boost Lab View
Ideal relationship: Vout = Vin / (1 − D). Visual gauge + readout.
Vin
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Vout
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D
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η
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Risk: —
Inductor (L) Switch PWM (D) Diode Output Duty cycle gauge D = — Visuals are informational only. Real converters require component, loss, and control-loop design.
Inputs & Settings
Use the ideal boost equation. Enter what you know; results update instantly.
Examples: 3.3V, 5V, 12V, 24V
Vout must be ≥ Vin for a boost in the ideal model
Valid range: 0 ≤ D < 1 (or 0%–<100%)
If provided, tool will show an estimated non-ideal output.
Show Work (step-by-step)
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Work is shown in base units (V, ratio) for clarity and consistency.

Boost Converter Formulas (Ideal)

Ideal continuous-conduction boost relationship: Vout = Vin / (1 − D)

  • Duty cycle: D = 1 − (Vin / Vout)
  • Output voltage: Vout = Vin / (1 − D)
  • Input voltage: Vin = Vout × (1 − D)
Real designs require losses (switch/diode/inductor), control loop, current limits, and ripple constraints.

FAQ

Why can’t duty cycle be 100%?

In the ideal model, D → 1 makes Vout approach infinity, which is not physically possible. Real converters hit limits long before that (losses, switch/inductor saturation, current limit).

What does efficiency (η) do here?

If you provide η, the tool shows a simple estimate of achievable output under losses (for quick planning), but the primary math remains the ideal boost equation.

Can Vout be lower than Vin?

Not for a boost in the ideal model. If you need step-down, use a buck converter tool.

Tool Info

Last updated:

Updates may include UI improvements, unit support, and calculation edge-case handling.