LED lights and accessories now dominate more than 1/3 of the total lighting industry, being especially popular in commercial applications where the lower power consumption, longer lifespan, and greener environmental impact they offer is of prime importance.
While having many advantages of alternative lighting, LED lights also require greater current control to prevent fluctuations in output, uneven brightness, flickering, and even burn-out. To avoid these problems, as well as to enhance performance in areas such as dimming and color-changing, a control device called a “driver” is needed.
CONSTANT CURRENT LED DRIVERS
In small LED light fixtures, drivers are already built in. But, for larger devices and commercial signs, a separate driver must be used. Most commonly, a constant current LED driver is used because they secure a constant electrical current regardless of the voltage level, which may often fluctuate.
Without a current-limiting device, your LED could easily experience “thermal runaway,” especially when outdoor temperatures surge in the hot summer months, and either burn out or simply have its lifespan significantly shortened.
CONSTANT VOLTAGE LED DRIVERS
Unlike constant current LED drivers, constant voltage LED drivers maintain a fixed voltage (usually either 12 or 24 VDC), which matches the manufacturers’ requirements for specific LED lighting products. The external driver maintains the required voltage, while current-limiting resistors built right into LED ropes, strings, strips, bars, clusters, and other multi-diode products.
A constant voltage LED driver will often be used when LEDs are arranged in series or in parallel circuits to ensure an identical current flow through all of the numerous diodes that have been connected together as a single sign or other lighting unit.
A slightly smaller lumens per Watt ratio will often be obtained when using a constant voltage LED driver instead of a constant current LED driver, but in very large-scale and complex arrangements, the overall cost will still be less. A constant voltage LED driver can only be used (and must be used) when a fixture requires a specific voltage, but this is no problem since, in such cases, it is likely to be the more cost-effective LED driver anyway.
Both constant current and constant voltage LED drivers have their own distinct advantages and situations in which they are the superior option. Though less commonly used than their counterpart, constant voltage LED drivers are usually more efficient with extremely large and/or multi-component signage.