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Boost Converter Inductor & Capacitor Calculator

Boost converters step up a lower DC input rail to a higher regulated output rail using high-frequency pulse-width modulated (PWM) switching.

DC input supply voltage.

Target regulated output voltage (must be higher than V_in).

Maximum continuous DC load current.

Operating switching frequency of the PWM controller.

Inductor ripple current fraction ΔI_L / I_in (typically 0.2 to 0.4).

Estimated power conversion efficiency (0.85 - 0.95).

Peak-to-peak allowed output capacitor voltage ripple.

Calculated Result
49.5 µH

Recommended Boost Inductance (L)

Minimum Inductance (L)

49.5 µH

Peak Inductor Current (I_pk)

5.11 A

RMS Inductor Current (I_rms)

4.46 A

Inductor Ripple Current (ΔI)

1.33 A (30%)

Operating Duty Cycle (D)

55 %

Average Input Current (I_in)

4.44 A

Min Output Capacitor (C_out)

220 µF

Output Power

48 W

Calculation Breakdown

  1. Duty Cycle CalculationD = 1 - (V_in · η / V_out) = 1 - (12 · 0.9 / 24) = 55%.
  2. Input & Ripple CurrentI_in(avg) = P_out / (V_in · η) = 48 / (12 · 0.9) = 4.44 A. ΔI_L = 0.3 · I_in = 1.33 A.
  3. Inductor SizingL = (V_in · D) / (f_sw · ΔI_L) = (12 · 0.55) / (100000 · 1.33) = 49.5 µH.
  4. Output Capacitor SizingC_out = (I_out · D) / (f_sw · ΔV_out) = (2 · 0.55) / (100000 · 0.05) = 220 µF.

Boost Converter Passives

Interactive visualization based on your current inputs

Value
0.014284155Inductance (µH)Capacitance (µF / 10)Peak Current (A × 10)Duty Cycle (%)ParameterValue

What Is the Boost Converter Inductor & Capacitor Calculator?

The Boost Converter Inductor & Capacitor Calculator sizes key energy storage passives for non-isolated step-up switching converters.

How Does the Boost Converter Inductor & Capacitor Calculator Work?

During switch-on, energy builds up in the magnetic field of the inductor; during switch-off, the inductor voltage boosts on top of the input rail to charge the output capacitor.

Boost Converter Inductor & Capacitor Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

L = \frac{V_{in} \cdot D}{f_{sw} \cdot \Delta I_L}, \quad C_{out} = \frac{I_{out} \cdot D}{f_{sw} \cdot \Delta V_{out}}

Sizes energy storage passives to maintain continuous conduction mode with controlled current ripple.

How to Use the Boost Converter Inductor & Capacitor Calculator

  1. Enter input voltage range and required boosted output voltage.
  2. Specify output load amperage and PWM switching frequency.
  3. Read required inductance, peak saturation current, and output capacitance.

Step-by-Step Example Calculation

12V to 24V 2A DC-DC Step-Up Supply

Input Values:

inputVoltage:12
outputVoltage:24
outputCurrent:2
switchingFrequency:100
rippleCurrentRatio:0.3
efficiency:0.9
outputRippleMv:50
Worked Steps: Requires 49.4 µH inductor with 5.14 A peak saturation rating, and 220 µF output filter capacitor.

Understanding Your Result

Recommended Inductance (L): Value needed for continuous conduction mode (CCM).

Peak Current (I_pk): Dictates required inductor saturation current (I_sat).

Min Output Capacitor: Prevents excessive output switching ripple.

Factors That Affect the Result

  • Higher switching frequencies permit smaller inductors and capacitors at the expense of higher MOSFET switching losses.

When Should You Use This Calculator?

  • Designing battery boost stages (e.g., 3.7V Li-ion to 5V USB), solar MPPT boost converters, and automotive LED drivers.

Assumptions & Limitations

  • Assumes CCM operation and ideal diode conduction drops.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Standard power electronics design equations.

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