Now grab a magnifier glass and be the detective to find out nerves (wires) of your cool back light. There will be following names in the board.

1. LED_EN or BL_EN

2. V_LED or VBL

3. LED_PWM

4. GND

We need only these 4 pins for our work.

Here the first pin is LED_EN as the name itself says it enables LED if powered high. According to my datasheet, this pin is named as LED_EN and rated as 3.3V.

Caution: Please check the voltage level before powering.

V_LED or VBL is VDD where we need to connect main supply voltage i.e 12V which will be boosted to the required voltage by the boost circuit and finally will be driven by the LED driver.

LED_PWM or PWM pin is where you provide the brightness control to the display. This is how your laptop display brightness is varied on your input Pulse Width Modulated signal. The measure is in terms of the duty cycle for the square wave PWM and is calculated as Ton/(Ton+Toff) i.e if Toff is zero PWM is 1 i.e 100%.

We will use the light as 100% bright.

The ground will be connected to ground.