What is the formula for Boost Peak Switch Current?

The Boost Peak Switch Current formula is Ipk = Iout/(1 − D) + ΔIL/2, where Ipk—Peak switch/inductor current (A); Iout—Output (load) current (A); D—Duty cycle (0–1); ΔIL—Peak-to-peak ripple current (A).

What does Ipk mean in the Boost Peak Switch Current formula?

Ipk is Peak switch/inductor current (A).

Boost Peak Switch Current

Q: How do you calculate Boost Peak Switch Current?

Use the formula Ipk = Iout/(1 − D) + ΔIL/2. The peak current in a boost converter’s switch and inductor is the average inductor current (the output current divided by 1 − D) plus half the ripple. Enter the values you know in the calculator above and it solves for the remaining variable.

Ipk = Iout/(1−D) + ΔIL/2

Calculator

Peak Current

Output Current

Duty Cycle

Ripple Current

Result

—

Formula

Ipk = Iout/(1 − D) + ΔIL/2

Description

The peak current in a boost converter’s switch and inductor is the average inductor current (the output current divided by 1 − D) plus half the ripple. This peak sets the saturation rating of the inductor and the current rating of the MOSFET and diode. Underestimating it leads to inductor saturation and runaway current.

Variables

Ipk — Peak switch/inductor current (A)
Iout — Output (load) current (A)
D — Duty cycle (0–1)
ΔIL — Peak-to-peak ripple current (A)

Practical Notes

The average inductor current Iout/(1−D) rises steeply as D approaches 1, which is why high step-up ratios demand large, low-saturation inductors and high-current switches.

Related Concepts

All Power & Efficiency formulas →

Linear Regulator Dissipation Efficiency Buck Converter Boost Converter Peukert Effect Energy After Losses Solar Charge Time LDO Minimum Output

Need more features?

Save calculations, import telemetry data, simulate battery discharge, and collaborate with your team.

Try the App