3. TECHNICAL BRIEF
- 40 -
Copyright © 011 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
There are four current source LED drivers in the RT8966. These current sources can be programmed via I2C in
the following control registers, Enable and LED Set. These registers include each driver's enable/disable
control, source current control, and LED brightness dimming.
The RT8966 provides a constant current for the white LEDs. Each channel supports up to 30mA current and
regulates a constant current for uniform intensity. In order to maintain LED constant current, the input
voltage must provide the required LED forward voltage and current source dropout voltage. If the forward
voltage of the white LEDs is 3.3V, the input voltage should be higher than 3.4V to provide enough voltage
headroom for maintaining constant brightness.
3.8.2 LCD Backlight Interface
Figure 3.8.2. RT8966 Block Diagram