I intend to use WF101FSYAPLNGO display model of winstar.
In its data sheet AVDD, VGH,VGL VDD, VDDT voltages are given. Can some one help to find the difference between AVDD and VDD? Is AVDD meant for back light control?
I am using conga ma-5 n4200 processor for my project, its design guide specifies that back light can be controlled by PWM or analog voltage via a i2c DAC. In the said display's datasheet they don't specify a back light control method.
Looks to me like the LCD panel needs each of those four supply rails, plus Vcom, plus Vddt (assuming you're using the touch function), plus another supply for the backlight.
The backlight will be a bit more than 12V (4 white/blue LEDs in series at a bit over 3V each) at about 480mA total at full brightness.
It's up to you how you get that supply and how you PWM it or whatever, but it should be current controlled since there are no series resistors or other circuitry. It's about a 6W power draw so a substantial LED driver is called for.
There are no end of semiconductor suppliers offering integrated circuit solutions for driving backlights.
Typically AVDD is the power supply for the analog part of the circuit. They are external so that you can add filters to reduce noise.
