LED Driver Sizing: Worked Examples
Sizing is arithmetic once you know the load. Two examples cover the common cases.
Example 1 — constant current
A COB module is rated 36 V at 700 mA. Power = 36 × 0.7 = 25.2 W.
- Pick a CC driver rated for 700 mA whose voltage window covers 36 V (e.g. 12–48 V).
- Add 20% headroom → choose a driver rated ~30 W or more at 700 mA.
Example 2 — constant voltage
A 24 V LED strip draws 4 A per 5 m section, two sections = 8 A → 192 W.
- Pick a 24 V CV driver. 192 W × 1.2 headroom = 230 W.
- Choose a 24 V / 250 W driver (or parallel smaller drivers per section).
The headroom rule
Always size to ~120% of the load. Running a driver near 100% load shortens life and risks thermal shutdown. See the master selection guide and how to read the label.