Introducing the LED Driver and Controlling LED Lighting Systems
LED is rapidly taking over homes, commercial, and buildings as the preferred form of lighting. Last year, Philips hit their one billion LED milestone and affirmed that it is on track towards achieving two billion LED lamps well ahead of 2020 target. This is evidence that it’s only a matter of time before LED totally relegates the other forms of lighting to the back banner.
Despite the profound popularity enjoyed by LED, many people are not aware of operated by a device called an LED driver. LED drivers are similar to ballasts in fluorescent tubes or transformers in voltage bulbs. The supply LED bulbs with the electricity they require to function.
Functions of LED drivers
LED drivers are primarily required for two purposes:
LED lights are designed to function at a low voltage of between 12 to 24VDC. However, most of the supplies offer 120 to 277V of AC power. LED drivers rectify these high AC voltages to direct current.
Voltage and current fluctuations
The light output of LEDs is directly proportional to its current supply. LED lights are rated to operate within a certain current range hence variations in current causes the light output to vary. Light output will also degrade faster owing to high temperatures within the LED.
Types of LED drivers
There are two types of LED drivers:
Internal LED drivers
Internal LED drivers are contained within the light bulb. They are mostly found in household bulbs since they make it easy to replace old incandescent or CFL bulbs with LED bulbs. This is the case for LED bulbs that have standard screw-in or plug-in bases, for instance, the E26/E27 or GU24/GU10.
There are some LEDs that particularly require separate driver since they are simpler and cheaper to replace compared to internal drivers or to LEDs. External drivers are ideal for LEDs used in cove lights, tape lights, downlights and outdoor-rated lights among others. External drivers can be further classified into three; constant current, constant voltage, and AC LED driver.
Factors to consider when choosing an LED driver
According to NEC outlines, LED drivers ought to be paired with LEDs that consume 20% less than the maximum rated wattage. Do not pair an LED driver with an LED that is at or exceeds the driver’s maximum wattage. This will result in overstressing the driver components.
Some LED drivers (constant-current and constant-voltage LEDs can be made with a dimming capability. However, both LED and drivers must specify that they are dimmable on the datasheet in order for the assertion to be made. In the event that the product data sheet does not mention it, it is safe to assume that the product is not dimmable. Dimmable external drivers are usually accompanied by other dimming control devices like the TRIAC, Trailing edge or 1-1-v dimmers.
Power factor describes how efficient the LED driver is. Power factor is expressed in a ratio that lies between 0 and 1. The closer to 1, the more efficient the LED driver. An ideal power factor should have a power factor of 0.9 and above.
Ingress Protection Rating
Ingress ratings determine the environmental protection that the outer casing offers the LED driver. The first number specifies protection against solids while the second specifies protection against water.
Despite the fact that they are less popular than LED light, LED drivers are very critical in the operation of LEDs. Therefore it is prudent to understand the kind of drivers you need before installing LEDs.