Constant Current LED Driver Technology

How constant current LED drivers power LED modules and light engines, and how to match current, voltage and power to choose the right driver.

Overview

What is a constant current LED driver?

A constant current (CC) LED driver converts mains power into a regulated DC supply that holds the current through the LEDs at a fixed value, such as 350mA, 700mA or 1050mA. The output voltage automatically adjusts to whatever the connected LEDs need, within the driver's rated voltage window.

LEDs are current-driven devices: their brightness, colour and lifetime depend on the current flowing through them, and a small change in voltage can cause a large change in current. Holding the current constant keeps light output stable and protects the LEDs. Our compact, non-dimmable CC drivers from Lifud, Snappy, LTECH and Philips Xitanium cover 4W to 60W, with output currents from 150mA to 1550mA.

Stable light output and colour from regulated current
Protects LEDs from over-current and thermal runaway
Compact housings for downlights, panels and luminaires
Flicker-free output on many models
Short circuit and over-current protection

Compact CC drivers at a glance

Brands: Lifud, Snappy, LTECH, Philips
Power: 4W – 60W
Output current: 150mA – 1550mA
Output voltage: 3V – 50VDC (model dependent)
Input: 100–240VAC or 220–240VAC
Dimming: Non-dimmable, fixed output
Connection: Push, screw or flying leads
Protection: Short circuit, over current

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The technology

Current, voltage window and power

Every CC driver has three key output ratings: the fixed output current, the output voltage window it can supply while holding that current, and the maximum power.

When LEDs are connected in series, the same current flows through each one and their forward voltages add up. If each LED has a forward voltage of around 3V, ten in series need about 30V. That total must fall inside the driver's voltage window, for example 25 to 42V.

The power drawn is simply current x voltage: 1050mA at 30V is about 31.5W, which must be within the driver's rated power.

Simplified illustration: the driver fixes the current, the LED string sets the voltage, and that voltage must sit inside the driver's output window.

CC vs CV

Constant current or constant voltage?

The LED product you are powering decides which type of driver you need.

Characteristic	Constant current (CC)	Constant voltage (CV)
What is fixed	Output current, e.g. 350mA, 700mA, 1050mA	Output voltage, e.g. 12V or 24V
What varies	Output voltage, within the window	Output current, up to the maximum
Use with	LED modules, light engines, COBs and high-power LEDs without current control	LED strip, chain modules and products with built-in current control
Wiring	LEDs normally in series	Loads normally in parallel
Typical applications	Downlights, panels, spotlights, luminaires	Strip lighting, signage, cove lighting

Powering LED strip? See our compact constant voltage LED drivers.

Our range

Compact CC drivers compared

Choose by power, output current and the voltage of your LED load.

Series	Power	Output current	Output voltage	Connection
SNP4 (miniature)	4W	350 / 500 / 700mA	3 – 12VDC	Flying leads, IP66
SP10 (miniature)	10W	350 / 500 / 700mA	4 – 29VDC	Flying leads
Snappy SE12	12W	300 – 350mA	14 – 40VDC	Screw terminals
Snappy SE15	15W	300 – 700mA	10.7 – 50VDC	Screw terminals
LTECH SN15	15W	150 – 350mA	9 – 42VDC	Push-in terminals
Philips Xitanium mini	10 – 48W	350 – 1050mA	See datasheet	Push terminals
Lifud LF-GIF040	18.75 – 44.1W	750 – 1050mA	25 – 42VDC	Push terminals
Lifud LF-GIF060YS	Up to 60W	1350 – 1550mA	30 – 40VDC	Push terminals

Benefits

Advantages of compact CC drivers

Why a matched constant current driver is the heart of a reliable LED luminaire.

Stable light output

Regulated current keeps brightness and colour consistent as LEDs warm up and supply voltage varies.

Longer LED life

Running LEDs at their rated current prevents over-driving and thermal runaway, protecting lifetime.

Compact size

Small, slim housings fit inside downlights, panels and track heads, or in the ceiling void beside them.

Flicker free

Low-ripple output on many models gives comfortable light with no visible flicker or camera banding.

Built-in protection

Short circuit and over-current protection as standard, with over-temperature protection on Xitanium drivers.

Wide choice

4W to 60W and 150mA to 1550mA from four leading brands, to match almost any LED module or light engine.

Selection guide

Choosing a CC driver in five steps

Find the LED current from the LED module or light engine datasheet, e.g. 700mA.
Add up the forward voltage of all LEDs or modules connected in series.
Check the voltage window: the total must sit within the driver's output range, ideally not at either end.
Check the power: current x voltage must be within the driver's rating.
Choose the format: input voltage, size, connection type, IP rating and whether dimming is needed.

Worked example

A downlight light engine rated at 700mA with a forward voltage of 33V:

Required current: 700mA
Load voltage: 33V
Power: 0.7A x 33V = 23.1W
Suitable driver: 700mA, window covering 33V, 25W+

Need dimming? See our DALI and dimmable options:

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4–60W

Power range

150–1550mA

Output currents

IP66

Miniature SNP4

Leading brands

Where compact CC drivers are used

Compact CC drivers power LED luminaires across commercial and residential lighting.

Downlights

Remote or integrated drivers for recessed and surface downlights.

LED panels

Slim drivers for edge-lit and back-lit panel luminaires.

Retail spotlights

Track and spot luminaires using COB and high-power LEDs.

Light engines

Circular, square and linear light engines in new luminaires.

Display & cabinets

Miniature drivers for display cabinets, furniture and small fittings.

Retrofit & replacement

Replacing failed drivers in existing LED luminaires.

FAQ

CC driver questions

A constant current (CC) driver holds the current at a fixed value, such as 350mA or 700mA, and lets the output voltage vary to suit the LEDs. It is used for LED modules, light engines and COBs without their own current control. A constant voltage (CV) driver holds a fixed voltage, such as 12V or 24V, and is used for LED strip and modules that have built-in resistors or current regulators.

Match the driver's output current to the current your LEDs are rated for, check that the total forward voltage of the LEDs falls inside the driver's output voltage window, and make sure the power (current x voltage) is within the driver's rating. Then choose the input voltage, connection type, size and IP rating to suit the luminaire.

The output voltage window is the range of voltages a CC driver can supply while holding its rated current, for example 25 to 42VDC. The combined forward voltage of the LEDs connected to it must sit within this range, ideally not right at either end.

Series connection is preferred, because the same current flows through every LED and each one runs at exactly the rated current. Parallel strings can share current unevenly unless the LED module is designed for it, so follow the module manufacturer's guidance.

A flicker-free driver supplies a smooth DC current with very little ripple, so the light output does not pulse. This improves visual comfort, avoids stroboscopic effects and prevents banding when the light is filmed or photographed.

Constant Current LED Driver Technology