Solid state light sources, such as but not limited to light emitting diodes (LEDs) and other semiconductor-based light sources, require a constant direct current (DC) voltage or current to operate optimally. During operation, the light source must be protected from line-voltage fluctuations. Changes in voltage can produce a disproportional change in current, which in turn can cause light output to vary, as solid state light source light output is proportional to current and is rated for a current range. If current exceeds the manufacturer recommendations, the output of the solid state light sources can become brighter, but that output can degrade at a faster rate due to higher temperatures within the device, which leads to a shorter useful life.
Solid state light sources, therefore, require a driver (also referred to as a driver circuit and/or a power supply) that converts incoming alternating current (AC) power to the proper DC voltage, and regulates the current flowing through the light sources during operation. The driver converts 120V (or other voltages) 60 Hz AC power to DC power required by the light sources, and protects the light sources from line-voltage fluctuations.