🔋 Buck Converter Calculator
Calculate the duty cycle and key component values for a buck (step-down) DC-DC converter design.
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What a buck converter does
A buck converter is a switching DC-DC power supply that steps a higher input voltage down to a lower, regulated output voltage efficiently.
The formulas used
In continuous conduction mode, the ideal duty cycle is D = Vout / Vin. A commonly used inductor sizing rule targets an inductor ripple current of about 30% of the output current: L = (Vin – Vout) × D / (f × ΔIL), where f is the switching frequency and ΔIL is the target peak-to-peak ripple current.
These are standard first-pass design estimates for power electronics; a real design also needs to account for component tolerances, efficiency losses, and output capacitor selection.
Last reviewed August 2026