Boost Converter Calculator

The boost topology\'s fundamental principle — using inductor flyback to generate a higher voltage than the input — was exploited long before it was formalized. Nineteenth-century induction-coil X-ray sources, Kettering\'s 1910 automotive ignition coil, and Tesla\'s resonant transformers all used the same basic mechanism: dump energy into an inductor, then rapidly interrupt the current to spike the voltage. The modern switching-regulator boost topology was formalized alongside the buck in the 1960s, when integrated PWM controllers made continuous high-frequency switching practical.

The unique challenge of boost design — the right-half-plane zero (RHPZ) in its small-signal control transfer function — was characterized in the early 1970s by researchers including Slobodan Ćuk at Caltech. The RHPZ causes boost converters to briefly decrease output voltage in response to a step load increase (because the switch duty has to drop momentarily to redirect inductor current to the output), making feedback compensation trickier than in buck topology. This is why boost control loops typically have lower bandwidth than buck loops of the same frequency.

Boost converters dominate applications where a battery voltage needs to be stepped up: single-cell LED drivers, USB hosts from lithium batteries, e-paper display bias generators, and solar MPPT chargers. Synchronous boost converters (replacing the diode with a high-side MOSFET) now reach 95%+ efficiency at multi-amp loads; pulse-skipping modes extend that efficiency to micro-amp standby currents.

Enter input voltage (lower), desired output voltage (higher), load current, switching frequency, and inductor/capacitor values. The calculator returns duty cycle D = 1 − V_in/V_out, average input current (which is higher than output current by the step-up ratio), peak inductor current, and output voltage ripple.

Rule of thumb: avoid step-up ratios above 5:1 in a single stage — above that, duty cycle approaches 90%+ and peak currents explode. Use cascaded boosts, flyback, or charge-pump topologies for very high step-ups. Inductor saturation rating must exceed peak I_L, and the output diode/switch must handle V_out reverse voltage plus any ringing. All math runs client-side.