An LED driver is an electrical circuit used to power a light-emitting diode (LED) . The circuit must provide sufficient current to light the LED at the required brightness, but must limit the current to prevent damaging the LED. LED drivers are designed to handle fluctuation load, providing enough current to achieve the required brightness while not allowing damaging levels of current to flow. There are two main types of LED drivers: constant-current and constant-voltage. Each type of driver is designed to operate LEDs with a different set of electrical requirements. Constant current LED drivers are used when light output should be independent of the input voltage fluctuation. They are found in many types of general lighting products, such as downlights, troffers, table/floor lamps, street lights and high bay lights, for which high current quality and precise output control are the priority. On the other hand, constant voltage LED drivers are used when the electrical load of the LED circuit is either unknown or fluctuates. LED drivers can be either internal or external to the LED bulb or fixture.

When selecting an LED driver, there are several things to consider, including the type of LEDs being used and how many, the forward voltage, recommended driving current, and whether dimming capabilities are needed. LED drivers can be low voltage DC input power or high voltage AC input power. LED drivers that use high-voltage AC power are called Off-Line drivers, or AC LED drivers. In most applications, using a low voltage DC input LED driver is recommended.

In summary, an LED driver is a self-contained power supply that regulates the power required for an LED or array of LEDs. The driver provides the LED with the electricity it needs to function and perform at its best. LED drivers are essential for ensuring optimal conditions for LEDs and avoiding thermal runaway.