LED Strip Technology: 2835, 5050, COB and FCOB — What the Numbers Mean for Power

LED strip lighting is specified in a shorthand that looks like a secret code: 2835, 5050, COB, FCOB, 60 LEDs per meter, 14.4W per meter. Each of these terms describes a physical reality about the strip — the LED package size, the chip arrangement, the density — and together they determine the electrical characteristics that a constant voltage driver must supply. For buyers and installers, understanding strip technology is the key to choosing the right driver, predicting the light output, and avoiding the mismatch between strip and power supply that causes most strip lighting failures.

The two-digit pairs in names like 2835 and 5050 are package dimensions. An 2835 package is 2.8mm by 3.5mm; a 5050 package is 5.0mm by 5.0mm. The package is the ceramic or plastic carrier that holds the LED chip(s) and provides the electrical and thermal connection to the strip. A 2835 package typically houses a single chip rated at 0.2W or 0.5W, while a 5050 package is larger and commonly houses three chips, allowing either higher total output or RGB mixing. The package size affects light distribution and thermal performance — a larger package can dissipate more heat from the chip — but the package alone does not determine brightness. What matters is the chip inside it and the current it is driven at.

COB stands for chip-on-board: the LED chips are mounted directly on the strip substrate and covered with a continuous phosphor coating, producing a continuous line of light rather than a series of visible dots. A 2835 or 5050 strip is a row of discrete packages — you can see the individual LED dots under a diffuser. A COB strip looks like a smooth, uniform light bar. FCOB (filament chip-on-board) is the newer variation, using a narrower filament-style substrate that allows tighter bending and an even more uniform appearance. COB and FCOB strips are popular for architectural and decorative lighting where the discrete LED look is undesirable.

The density and power rating determine the electrical load. A strip is rated in watts per meter — 4.8W/m, 9.6W/m, 14.4W/m, 19.2W/m are common — and the driver must be sized for the total installed length. A 5-meter length of 14.4W/m strip draws 72W; on a 24V bus that is 3A, well within a 100W driver's 4.16A output but requiring attention to the 80 percent loading rule and the voltage drop along the strip. The current draw per meter also determines the internal voltage drop: a high-density 19.2W/m strip draws more current per meter and therefore loses more voltage along its length, which is why high-power strips are usually run at 24V rather than 12V.

Voltage selection is the decision that most affects the driver. At 12V, a strip draws twice the current of the equivalent 24V strip, which doubles the internal drop along the strip and quadruples the copper loss in the supply cable for a given conductor size. A 12V strip of 5 meters at 19.2W/m draws 8A; a 24V strip of the same rating draws 4A. For runs longer than a couple of meters, 24V is the practical choice, and this is precisely the class of product that the PV100-type driver serves: 24V constant voltage output, sized to the strip's wattage with margin. The driver's output current must meet or exceed the strip's current draw, and the total should be held at or below 80 percent of the driver rating for reliability.

The other specification that matters is the color temperature and the CRI (Color Rendering Index) of the chips, which do not affect the driver selection but do affect what the customer sees. What affects the driver is only the electrical load: wattage per meter, total length, and operating voltage. A buyer can therefore match driver to strip by arithmetic alone: total wattage = watts per meter times length; current = total wattage divided by voltage; driver rating = current times 1.25 for the 80 percent rule. That arithmetic, done before purchase, prevents the most common strip lighting failure — the driver that is undersized, runs hot, and fails within months.