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Buck Converter Calculator

Design and analyze buck (step-down) DC-DC converters for power electronics.

Enter Design Parameters

Buck Converter Circuit

Buck Converter Circuit

Input Voltage (V_in):

Output Voltage (V_out):

Output Power (P_out) [W]:

Inductor Ripple (%) :

Switching Frequency (Hz):

Enter all parameters and click Calculate.

Buck Converter Examples

Example 1

Given: V_in=200V, V_out=56V, P_out=840W, Ripple=10%, f_sw=50kHz

Duty Cycle: D = 56/200 = 0.28 or 28%
Output Current: I_out = 840/56 = 15A
Inductor Ripple: ΔI_L = 0.1×15 = 1.5A
Inductor: L = (200-56)×0.28/(1.5×50000) = 0.0005376 H = 537.6 µH
Capacitor: C ≈ 0.93 µF (ΔV_out = 5.6V)
Load Resistor: R = 56/15 = 3.73 Ω

Example 2

Given: V_in=24V, V_out=12V, P_out=60W, Ripple=20%, f_sw=100kHz

Duty Cycle: D = 12/24 = 0.5 or 50%
Output Current: I_out = 60/12 = 5A
Inductor Ripple: ΔI_L = 0.2×5 = 1A
Inductor: L = (24-12)×0.5/(1×100000) = 0.00006 H = 60 µH
Capacitor: C ≈ 2.5 µF (ΔV_out = 0.24V)
Load Resistor: R = 12/5 = 2.4 Ω

Example 3

Given: V_in=48V, V_out=24V, P_out=120W, Ripple=15%, f_sw=75kHz

Duty Cycle: D = 24/48 = 0.5 or 50%
Output Current: I_out = 120/24 = 5A
Inductor Ripple: ΔI_L = 0.15×5 = 0.75A
Inductor: L = (48-24)×0.5/(0.75×75000) = 0.000213 H = 213 µH
Capacitor: C ≈ 1.67 µF (ΔV_out = 1.2V)
Load Resistor: R = 24/5 = 4.8 Ω