The switch to LEDs isn’t just about trading your old light fixtures for new ones. Just like fluorescent lights need ballasts to function properly, your LED lights need something called a driver. Sometimes, in smaller LED fixtures, drivers are build right in. But, if that’s not the case for your lighting system, you’ll need to pick one out for yourself. If you’re unfamiliar with the LED driver, what it is, how it works, and the many varieties available, this post will teach you everything you need to know.
Let’s start with a basic definition:
An LED driver is an electronic device that supplies power to LED lights. To ensure the LEDs function properly, the driver converts line power to the appropriate voltage (typically between 2 and 4 volts DC for high brightness LEDs) and current (around 200-1,000 milliamps or mA). Drivers might also include dimming or color correction controls.
All this ensures that your LEDs will operate with a steady lumen output and no variation.
Before we go any further, you should note that the quality of your driver will have a significant impact on your LEDs. A good driver is about 85% efficient, reducing the efficiency of the LEDs it powers by about 15%. To make sure that your LED lighting system is the most efficient, you need to make sure you’re using the right kind of driver. Finding your perfect driver depends on such factors as the type and number of LEDs you’re using, whether you’ll place them individually or in a series, any size limitations you may have, and of course, your installation’s main design goals.
What are the options? Types of LED drivers.
There’s one main distinctions here: Constant voltage vs. Constant current. You should pick your driver depending on the type of LEDs you plan to operate, and how you plan to operate them.
Constant current drivers fix the current supplied to the LEDs, but allow the voltage to vary depending on the load. They’re most often used when each light fitting requires its own driver; when you know the load or number of LEDs you’re going to use before installation, and want optimal efficiency. You’ll frequently find a constant current driver used to power a recessed downlight or a track light fixture, for example.
Constant voltage drivers supply a fixed voltage, usually 12VDC or 24VDC, and use a series of resistors or built-in regulators to control the current supplied to the LEDs. These are best for use with lighting systems that need more flexibility with the number of LEDs connected to a single power supply. As you add LEDs, the current will increase until it reaches the maximum limit. Constant voltage drivers are the popular choice to power things like sign lights and architectural lighting.
No matter which kind of driver you choose, the total wattage of the LED lights connected to the driver should never exceed the driver’s wattage rating.
Special Features: Dimming and Color Correction.
If you plan to integrate dimming or other specialized lighting controls like color correction or color changing controls, occupancy sensors, photocells, remote controls, or automation controls, be sure to verify that the driver you plan to use is compatible with your system. Most LED drivers, especially the new electronic ones, should work with these commercially available 0-10V control devices.
A properly functioning dimming system can work by reducing the forward current, using pulse width modulation (PWM) via digital controls, or implementing more sophisticated methods. It will allow you to dim the LED lights from 0-100%, maintain the lights’ color and color temperature, and prevent flickering. Dimming should also increase efficacy and lamp life.
Drivers can implement color changing and sequencing in a lighting system by either dimming an array of different colored LEDs, or working with a color sequencer. The sequencer functions by receiving the 10V or 24V driver output and converting it into a 3-channel output (customarily red, blue, and green) that can mix to create a wide range of hues.
For more information about the functions and benefits LEDs and LED drivers, check out this article from Plant Engineering, and this article from LEDs Magazine.
What questions do you have about LED drivers? Our lighting experts are ready to answer your questions!