P-Dim # 2 ?

[capwizard]

I would like to know what is P-Dim # 2?

Is that means the TV, LG 55" ccfl, has double dimming control signals, for what purpose needs A-dim, p-dim#1 and p-dim#2?

[budm]

Re: P-Dim # 2 ?

A-Dim = Analog dimming control Voltage
P-DIM 1, 2 = PWM dimming.
The board can be stuffed in many way to meet the many TV model requirement. a-DIM is hardly used these day. You will use one (Analog) or the other (PWM) depend on the design requirement.
Use your scope for PWM and DC meter for the analog to see what you have when you adjust the backlights level. The values may go up and down if the dynamic contrast is turned on.
One example of multiple PWM dim controls, this one has 4 for zones control.

[capwizard]

Re: P-Dim # 2 ?

Thank you for the circuit diagram that is the one worth collecting, because I'm studying SLC 2013M LED driver IC, I will test later on, I'm very interested in that. but this tv needs a mainboard, I did over reflow on it.

Can I have a question? Epwm, E is an abbreviated form?

[budm]

Re: P-Dim # 2 ?

E = External.
See the spec sheet page 12. In the old day of LCD panel, you can control dimming of the backlights in many ways, depend on the TV manufacturers choosing.

[capwizard]

Re: P-Dim # 2 ?

Min Typical Max
External PWM Duty ratio D_EPWM 30 100 %
External PWM Frequency F_EPWM 150 180 300 Hz

on page 10
EPWM = Open/High (Turn on for 45minutes) what does this mean?

I found it:
warm-up procedure: Stable for 45 minutes in dark environment at 25oC. Does it take so long to stabilize, warm-up LED panel?

contrast ratio (CR) picture 1