Three Things To Note About LED Drivers

LEDs operate from DC and are relatively easy to work with but there are three points that help understand regarding the role of an LED driver:

• Voltage: LEDs in a backlight will be wired in series so in each LED requires 3v and there are 20 LEDs the voltage required will be 60v.
• Current: The driver will maintain a constant current to the LED’s.
• Brightness control: Two normal methods to control brightness are by varying the current or using a technique called Pulse Width Modulation (PWM*).

For a display system design perspective the complex work is done by the LED driver design and usage is as straightforward as following the connection specifications.

* PWM creates the impression of lower light by switching the LEDs on/off but at a frequency faster than our perception. Using PWM the brightness can be lower than achievable by simply reducing the current.