Doing reverse engeneering to a IK-CVB20 Pegatron "inverter" board from an HP Pavilion 20f295la I found there is no real dim signal from Mobo.
Pin 1= GND
Pin 2= GND
Pin 3= Enable (works with 5 volts)
Pin 4= Pseudo Dim pin (i will explaint below)
Pin 5= Panel type selector (options are Samsung, LG and CMI, selected by jumpers in the board)
Pin 6= Same as Pin 5.
Link to the image https://imgur.com/gcTkPuK
That board works with a MPS MP3389 controller and needs a dim signal (pin 6) it works with a PWM signal or a DC voltage (0 to 1.2).
In that Pegatron board is configured to work with a PWM and 3389 dim pin is connected to a PWM generator ( Richtek r7731a ).
The problem is: the supposed dim pin in board connector (pin 4) go directly to r7731a 's VDD pin not to any PWM control pin as expected.
r7731a's Vdd have a very narrow range of operational voltages from 10 to 14v
changing that voltage will not work as a dim signal: In r7731a datasheet is no mention of behavior changes vs VDD value.
***r7731a Datasheet
Then, how HP mobos do a dim function with these Pegatron boards? Someone have an idea?
Pin 1= GND
Pin 2= GND
Pin 3= Enable (works with 5 volts)
Pin 4= Pseudo Dim pin (i will explaint below)
Pin 5= Panel type selector (options are Samsung, LG and CMI, selected by jumpers in the board)
Pin 6= Same as Pin 5.
Link to the image https://imgur.com/gcTkPuK
That board works with a MPS MP3389 controller and needs a dim signal (pin 6) it works with a PWM signal or a DC voltage (0 to 1.2).
In that Pegatron board is configured to work with a PWM and 3389 dim pin is connected to a PWM generator ( Richtek r7731a ).
The problem is: the supposed dim pin in board connector (pin 4) go directly to r7731a 's VDD pin not to any PWM control pin as expected.
r7731a's Vdd have a very narrow range of operational voltages from 10 to 14v
changing that voltage will not work as a dim signal: In r7731a datasheet is no mention of behavior changes vs VDD value.
***r7731a Datasheet
Then, how HP mobos do a dim function with these Pegatron boards? Someone have an idea?
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