TPS61165: LCD Backlight going from 8V to 4V after 5-10 second bootup.

user6122518

Part Number: TPS61165

All our CCA that uses this circuitry to drive a LCD Backlight and are working fine except a few.

The issue we have is the output is adequate for the Backlight to work but after 5-10 second after boot up the output voltage drops.

Short from replacing the TPS61165 we have investigated the whole circuitry for faulty parts, shorts, bad soldering, you name it.

After reviewing the Forums i haven't found any issues similar to mine.

Anyone may possibly have an theory?

What could possibly cause the Driver to drop its output from 8V to 4V with an input of 5V?

over 6 years ago

0 Sean Zhou over 6 years ago

TI__Mastermind 22745 points

Hi Sir,

Do you have the schematic and what's the detail problem? What's the maximum output current?

Regards

Sean

0 user6122518 over 6 years ago in reply to Sean Zhou

Prodigy 40 points

ILED = 220mA (Max) "For all 11 modules of 3 LED in series"

The issue we have is with the LCD screen backlight voltage drops, be it connected to an LCD Screen or not. We have tried multiple LCD screens and the issue persist.

Again as mentionned earlier, the issue occurs with a few of our elctronic boards. We haven't replaced the TPS61165 yet as we lack a new part to replace it with.

0 Sean Zhou over 6 years ago in reply to user6122518

TI__Mastermind 22745 points

Hi Sir,

The schematic seems ok, I have some suggestions for you:

1. Have you tried to exchange the devices or boards?

2. How about the thermal performance?

Regards

Sean

0 user6122518 over 6 years ago in reply to Sean Zhou

Prodigy 40 points

1. If your refering to another board that has a TPS61165 connected to the same LCD screens used on the board in trouble, we sure did. And as mentionned we've used more than one LCD Screen.

2. The area of the board with the TPS61165 circuitry does not go higher than 38 'C. And the IC seems to stay around 24 'C on power up. And MBR0540 stays around 38 'C but once the TPS61165 seems to shut down, all the components around including the MBR0540 drops to room temperature.

0 user6122518 over 6 years ago in reply to user6122518

Prodigy 40 points

We have swapped the TPS61165 with another we had from a spare scrapped board. The issue was resolved. Seemed the other TPS61165 migth have been dead.

0 Sean Zhou over 6 years ago in reply to user6122518

TI__Mastermind 22745 points

Hi Sir,

Ok, get it, any further question, please let me know.

Regards

Sean

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TPS61165: LCD Backlight going from 8V to 4V after 5-10 second bootup.