This buck converter calculator estimates duty cycle and minimum inductance for ideal continuous-mode voltage conversion.
Physics
Buck Converter Calculator
Estimate ideal buck-converter duty cycle and minimum inductance.
Calculator
About this calculator
Formula notes
duty = output voltage / input voltage x 100; minimum inductance = (input - output) x output / (input x ripple current x frequency).
Worked examples
- Example: 12 V input, 5 V output at 100 kHz with 0.5 A ripple gives a duty cycle near 41.7%, and minimum inductance about 58.3 H.
- With 4 V input, 2 V output at 100 kHz, and 0.5 A ripple, the ideal duty cycle is 50% and minimum inductance is 20 uH.
How to use it
- Enter input and output voltages.
- Set switching frequency and desired ripple current.
- Read the ideal duty cycle and minimum inductor value.
Frequently asked questions
Does this include losses?
No. Inductor resistance, switches, rectifier drops, and loop delays are not modeled.
Can I use this for continuous operation?
The result is a primary estimation for continuous-mode design; choose rated and margin values for real hardware.
Limits and interpretation
- The design assumes ideal continuous-mode conversion; losses, parasitic capacitance, feedback, and startup conditions are missing.
- Choose inductors rated for temperature, saturation current, and AC resistance, not only the calculated minimum.