All led power supplies are either constant voltage (CV) or constant current (CC) or both. This is one of the primary factors you need to consider while you are choosing a suitable one for your project. Normally to say, LED Downlight, Residential LED Lighting, Retail Lighting, Mood Lighting will use constant current led driver. Moving Signs, Stage Lighting, Architectural Lighting, strip lighting, led bar will use constant voltage led driver.

When using a constant current LED driver, pay attention to the current requirements of LED(s). LEDs data sheets state what they will need, with the value given in amps (A) or milliamps (mA). There are also drivers with variable and multi- output current, they give either a range, for example 100 mA to 500 mA, or stepped values like 350 mA, 500 mA, 700 mA. The working current of LED must fall within the chosen value(s), lower current to help extend its life, higher current could wear the LED out quicker.

The power of driver must higher than LEDs required for safety. If the wattage is equivalent to the LED power requirements, it is running at full loading may shorter driver’s life span. 80% maximum loading will be best for a driver.

For constant voltage drivers, it requires the same output voltage as your LED’s voltage requirements (12v, 24v, 36v,or 48v), adding each LED voltage requirement together for a total value for multiple leds. If you  use constant current power supply, the output voltage must exceed 5-10v of the LED requirements.