Power management
Boost Converter (Step-Up DC-DC)
Step-up switching converters when you need more voltage than your input rail provides.
What is it?
A boost converter steps a lower input voltage up to a higher output. Storage inductor on the input, switching transistor to ground, freewheel diode (or sync FET) to the output cap. Used wherever the available rail is below what the load needs — e.g., single-cell battery driving a 12 V backlight, or USB 5 V driving a 24 V industrial sensor.
When do you need it?
- Single Li-ion cell (3.0-4.2 V) up to 5 V or higher.
- LED backlight or string driver (current-mode boost).
- USB-powered devices needing >5 V internal rail.
- Solar / energy-harvesting front-ends boosting from a low PV voltage.
- Audio amplifier rails (single-supply battery up to ±15 V).
How to pick the right one
- VIN range
- Must include your worst-case minimum (e.g., 2.7 V for a discharging Li-ion).
- VOUT (max)
- Has practical upper limit — boost duty cycle approaches 100% as Vout/Vin grows. Above ~5× ratio, consider SEPIC or flyback instead.
- IOUT
- Critical: average inductor current is much higher than output current (IL = IOUT × VOUT/VIN). Make sure the switch can handle it.
- fSW
- 500 kHz-2 MHz typical. Higher = smaller passives.
- Output type
- Constant voltage (most common) or constant current (LED drivers).
What Magnias offers
Magnias offers boost converters for portable, LED-backlight, and small-rail step-up use cases, spanning input ranges from 1.8 V to 24 V, output up to 30 V, and integrated-switch parts up to 2 A.
Common questions
Can a boost converter survive a short on the output?
Only if it has explicit short-circuit protection. Many basic boosts will overheat because the input-output diode path is always there even with the switch off. Pick a part with OVP and OCP.
Why does my boost have ringing on the switch node?
Parasitic inductance between input cap and switch creates LC ringing at the FET drain. Add a small RC snubber, or use a part with internal slow-edge driver.
Boost or SEPIC?
Boost needs Vout > Vin always. SEPIC handles both — Vin can be above or below Vout. Use SEPIC for wide-range battery / solar inputs.