I actually have one of these boards and I know you're frustration.
For clarification this is the board:
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The red socket is meant to be used with backlights of small screen that can run from a 5V supply, typically this is probably a screen size up to 10". The problem here is that your inverter/LED driver (depending on which you have) is likely to require 12V so what to do?
Well here's what I did. As i mentioned in a post I replied to today, I used an LM2596 step down module, a cheap CCFL tester and a 12V power supply.
The cheap CCFL Inverter tester I used:
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I ran the 12V straight from the power supply to the tester, and from the tester to - in my case - an LED driver board. I then tapped of the 12V from the power supply to the LM2596 and stepped it down to 5V to driver the MT6820-B, and connected the output of the LM2596 to 5V and GND on the red connector. Problem with this setup is that you have 2 separate circuits, one for driving the LCD and the other for driving the backlight, they are not linked. This means that you manually have to switch the backlight on to see the picture.03.11.2016 - The following part regarding how I got the backlight to work with the LVDS controller has been shown to me to be, let's say, a little bit pointless. I've kept it in this post for reference, and you can read why it's pointless in the next post by Ertew. All I can say is, we all make mistakes.
The way I got around this problem was with a simple additional circuit. The additional circuit was comprised of an IRL540N HEXFET and a resistor, and works by utilizing the BL pin of the LVDS controller.
Here's the circuit:
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When the LVDS controller is power on, the BL pin goes HIGH pulling the 'Gate' pin of the IRL540N high, this effectively turns the IRL540N 'ON' allowing current to flow from the 'Drain' to the 'Source'. This is like physically flipping a switch from 12V to the CCFL inverter tester. When the LVDS controller is turned 'OFF' or put in standby, the BL pin goes low and turns off the CCFL tester.
The resistor value should be fairly high, I think I used a 57Kohm as I had one laying around, but any value above 10Kohm will probably be fine. The resistor is just there to hold the 'Gate' of the IRL540N 'LOW' when the LVDS controller is turned off.