boost converter calculator

What this boost converter calculator does

A boost converter steps a lower DC voltage up to a higher DC voltage. This calculator helps you quickly size the major energy storage components and estimate electrical stress so you can move faster from idea to prototype.

It is especially useful for common designs such as battery-powered systems, LED drivers, instrumentation rails, and embedded electronics where a higher voltage rail is needed from a lower source.

Core equations used

1) Duty cycle

The ideal relationship for a boost converter is:
Vout = Vin / (1 - D)

This calculator also includes efficiency in the duty estimate to provide a more practical first pass:
D ≈ 1 - (Vin × η) / Vout

2) Inductor sizing

Average inductor current in a boost converter is close to input current. Once ripple current is selected, inductor value is estimated by:
L = (Vin × D) / (ΔIL × fsw)

3) Output capacitor sizing

For a first-order estimate of output capacitance:
C = (Iout × D) / (fsw × ΔVout)

Real capacitor selection should include ESR, temperature effects, DC bias behavior, and transient requirements.

How to use the results

• Duty cycle: Indicates control effort. Very high duty cycles can reduce efficiency and stability margin.
• Inductor value: Starting point for selecting a standard inductor with adequate saturation current.
• Peak inductor current: Must remain below inductor saturation and switch current limits with margin.
• Output capacitor: Starting capacitance target before ESR and ripple current checks.
• CCM boundary inductance: Helps determine whether your design is likely continuous conduction mode.

Practical design tips

Selecting the switch (MOSFET)

Choose a MOSFET with voltage rating above output voltage plus spikes, and current rating above peak current with safety margin. Check R_DS(on), gate charge, and switching losses at your chosen frequency.

Selecting the diode (or synchronous rectifier)

For diode-based designs, use a fast or Schottky diode with low forward drop and sufficient reverse voltage rating. At higher power, synchronous rectification can significantly improve efficiency.

Layout matters

Keep high di/dt loops compact, place input/output capacitors close to switching nodes, and use a solid ground strategy. Poor layout can destroy performance even when calculations are perfect.

Limitations of this calculator

This is a fast engineering estimate, not a substitute for full converter design validation. It does not model:

• Controller compensation network design
• Switching transition losses and dead-time effects
• Magnetic core losses and thermal limits
• Start-up behavior, fault protection, or EMI compliance

After sizing components here, verify with datasheets, simulation, bench measurements, and thermal testing.

Quick FAQ

Can I enter very high output voltage ratios?

You can, but very high duty cycle designs become challenging. Consider multi-stage architectures or different topologies when needed.

What ripple percentage should I choose?

A common starting point is 20–40% inductor ripple relative to average inductor current. Lower ripple often means larger inductors.

Is this suitable for production design?

It is suitable for early sizing and learning. Production designs require full electrical, thermal, reliability, and compliance validation.