Power Control TFT/LCD Display (Gate Driver / Source Driver)

Hello Klaas,

Do you have any feedback for us?

Best Regards.
Ilona

Thanks for your feedback!

I have been busy with it for a while now, have been exploring different kind of chips / datasheets.

Regarding to the Backlight Driver, is it possible to supply this directly with, lets say... 10V? Without making use of any driver?
I do have only 1 channel, regarding to the datasheet (SPF-PH800480T024-IHC01_001)

Some options I have seen is making a combination between the TPS65124 and TPS61169

This actually is similar to the TPS65142 now I look at it.

The WLED output is 40VDC / 1,5A, this is adjustable... this can be done by using an PWM signal. Are there any other options? Potentiometer?

Are there any reference designs available? (Altium files? Or something else?).
Is there an QFP / TSSOP / other package available?

I just did some research:

Another option is the TPS65100 combined with TPS61169? In this case the packages are TSSOP and SC-70. 

Is this an good idea?

Those are so far my questions.

Best regards.

Klaas

Hello Klaas,

Thanks for the update. In the table below I have summarized and pointed out the main differences between the three solutions. I exchanged the TPS6124 with the TPS65121 as this integrates an LDO to supply the digital rail.

I would recommend to go with the (3) solution as this will save you the additional vcom-buffer that you need in the other solutions. Do you have any place constraints?

(1) TPS65121+TPS61169	(2) TPS65142	(3) TPS65100 + TPS61169
External WLED Driver Solution	Integrated WLED Driver	External WLED Driver
No VCOM Buffer	VCOM Buffer	VCOM Buffer
Auxiliary Rail for VIH/VIL	No Aux. Rail	Auxiliary Rail for VIH/VIL
Regulated VGH	Regulated Charge Pumps	Regulated Charge Pump
--	Not capable to supply 210 mA output current (max. 150 mA)	--
QFN + SC70	WQFN	QFN + SC70
EVM available	Request EVM	EVM available

 

To your question about the output voltage of the LED driver, I have notified the LED driver team, they are the expert for this part.

Best Regards.

Ilona

Hi Klass,

The TPS61169 can provide the power you need for the backlight. This device has PWM input for dimming the backlight. Let me know if you need anything else.

Best regards,
Randy

Thanks for uploading a table with  the possible solutions.

Well, I do not have place constraints yet. I cannot imagine that this part is taking a lot of space though.

So far we have seen is solution (3) our main goal. We will develop our PCB.
When the times comes I will give an update in here?

Is there any component list available or Altium Library? I see that there is used some schottky diode's, but there aren't any values. Although, the datasheets does say some specification on how to choose an Schottky.
And Altium library? I can convert the IC's itself to Altium. But I assume that there is a reference design available? This would make it a lot easier to develop.

Best Regards,

Klaas

Hi Klaas,

Sure you can send me the schematic and I can check it. However I think if you stick with the recommendation of the EVM you should'nt need my help.

Unfortunately the EVM has not been developed with Altium, I can only share the gerber-files with you as well as the BOM, see attached. You can convert the IC to Altium if required.hpa030a_bom.xlsHPA030A_gerbers.ZIP

If you have problems with the design, let me know.

Thank you.

Best Regards.

ilona

Hello!

This is an update regarding to developing our TFT Powercontroller.

We have been busy with testing and we came to the following results:

First, this is our design:

TFT Power Controller:

 

And the TFT Backlight Controller:

Voltages checked:

VDD INPUT: 5V (+5V_IND)
AVDD: 10.48V
VCOM: 3.83
DVDD: 3.3V
VGL: -6.9V
VGH: 20.8V (it has to be 16V??)

Calculations made for VGH:

1.214*(1+680K/56K) = 16V

Why do we have 20.8V?
Did we do the calculation wrong?

--- Update (2017-3-13 ; 15:05)

We soldered a 0R resistor at R6, our problem has been solved.
We misunderstood the Doubler / Tripler effect.

About the backlight Controller:

Is it possible to control it with just a simple 0-5V Voltage? Or does it really need to be controlled by PWM?

Output measured is arround 5V?

Looking forward to some answers!

Klaas

Hi Klaas,

The TPS61169 backlight controller can be used as on/off by setting PWM input = 5V/GND, otherwise you need PWM to controll backlight dimming.

Let me know if you need anything else in regard to the TPS61169.

thanks,
Randy