What Is an LED Driver and What Does It Do?
An LED driver converts mains AC into the regulated DC voltage or current an LED load needs. Learn the two output modes, sizing rules and failure modes.
Towe Engineering · Published November 2, 2026 · 3 min read
An LED driver is the power conversion unit between mains electricity and an LED load. It converts 110–265 V AC into regulated DC — either a fixed voltage (12 V or 24 V) for strips and light boxes, or a fixed current for bare LED modules. The driver also provides protection against short circuits, overload, overvoltage and over-temperature, and its quality determines the lifetime of the entire lighting installation, not just of one component.
Key points
- An LED driver converts 110–265 V AC mains into regulated 12 V or 24 V DC output
- Constant voltage for strips and light boxes; constant current for bare LED modules
- Size the driver to the load wattage plus 20% headroom
- The driver, not the LED strip, is what usually fails first in a cheap installation
The short definition
An LED driver sits between the wall and the light. Mains electricity is 110–265 V alternating current at 50/60 Hz; LED chips need low-voltage direct current at a tightly controlled level. The driver performs that conversion, holds it steady while the load and the mains wander, and protects both sides when something goes wrong.
That is why a lighting installation is only as good as its driver. The LED strip itself is nearly passive; the driver is the component doing active work every second the light is on.
The two output modes
| Mode | Output held fixed | Used for | Example |
|---|---|---|---|
| Constant voltage (CV) | 12 V or 24 V DC | LED strips, light boxes, cove lighting, luminous characters | Towe TF series, 60–600 W |
| Constant current (CC) | e.g. 350 mA, 700 mA, 1 A | Bare LED modules, COB boards, floodlight engines | Towe TD series (CV + CC dual control) |
Strip products contain their own current-limiting resistors, so they want a fixed voltage. Bare modules have no such circuitry, so the driver must fix the current instead. Connecting a CV driver to a module that expects CC — or the reverse — is the single most common specification error we see in enquiries.
Sizing: the 20% rule
Add up the wattage of everything on the output, then add 20% headroom:
- 8 m of 24 V strip at 10 W/m = 80 W → use a 100 W driver
- Six 12 W track spots = 72 W → use a 100–150 W driver
The headroom is not marketing margin. Drivers running at exactly 100% of rated power run hotter, and heat is what ages the electrolytic capacitors that dominate driver lifetime.
What a good driver does beyond conversion
A production-grade driver carries four protections as standard — short circuit, overload, overvoltage and over-temperature — plus a wide 110–265 V AC input window so that grid sag and surge in export markets stay inside the operating envelope.
Behind the datasheet, the difference between suppliers is process: in-circuit testing of every board, 100% full-load aging on every finished unit, and verified potting on waterproof models. Towe holds a field failure rate at or below 0.03% across millions of shipped units on that process — which is the number that actually predicts your maintenance cost.
This article describes general manufacturing practice for machined and fabricated components. It is not a substitute for a drawing-specific engineering review — tolerances, material selection and process capability depend on the individual part.