TPS65150: Devices shutsdown at longer distance between LCD & driver

Sudha kp

Prodigy 50 points

Other Parts Discussed in Thread: TPS65150

We are using TPS65150 LCD driver to drive display. We are using exactly same as application notes reference design.

It works fine with short distance between driver and LCD panel.

But one of new requirement is to increase the distance between the LCD panel and the driver by about 15cm long.

With this increase in length the driver getting very hot and display goes blank and all the o/p voltages drop to 0V.

Let us know is the long distance is over loading the driver. How to prevent getting hot and shutting down?

over 8 years ago

0 Ilona over 8 years ago

TI__Expert 8010 points

Hello Sudha,

Can you prove what you are seeing with scope plots? What is the input voltage of your system? I can imagine that the longer distance will cause a higher voltage drop on VIN which may hit the UVLO and then the device get into shutdown, but this needs to be proven.

Thank you.
Best Regards.
Ilona

0 Brigitte over 8 years ago in reply to Ilona

TI__Guru 65300 points

Hello Sudha,

Could you reproduce a VIN drop on your system with the longer cables?

Best regards,
Brigitte

0 Sudha kp over 8 years ago in reply to Brigitte

Prodigy 50 points

Hi Brigitte,

Sorry for the late reply. The voltage will drop to 4.88V the moment power ON the supply even with out cable and IC will get very hot and no O/P voltages. Does this mean the IC65150 already spoilt. Do you have any clue?

Thanks for your support.
Regards,
Sudha

0 Brigitte over 8 years ago in reply to Sudha kp

TI__Guru 65300 points

Hello Sudha,

Please measure the input voltage directly at the IC with a scope while the IC is turned on.
Is it possible that there is no input capacitor connected directly to the IC?

Best regards,
Brigitte

0 Sudha kp over 8 years ago in reply to Brigitte

Prodigy 50 points

Hi Brigitte,

We are using 22uf 16V capacitor at the I/P. Once I power on the voltage will drop to 4.8V which is measured across C7.

Could be capacitor C9 are C7 might have spoilt

Regards,

Sudha

0 Ilona over 8 years ago in reply to Sudha kp

TI__Expert 8010 points

Hello Sudha,

Thanks for the update. Is there anything else connected on the 5-V rail or only the TPS65150?
If it is only this device how much current does it draw when you turn it on (supposed to be 48 +/- 1m A) ??
How about the scope plots Brigitte and I were asking, is it possible to monitor the startup - shutdown moment (including VIN, I(IIN) and VS)?

Thank you!
Best Regards.
Ilona

0 Ilona over 8 years ago in reply to Ilona

TI__Expert 8010 points

Hello Sudha,

Do you have an update on this? Please let us know if you have any more questions otherwise I will close this thread.

Thank you.
Best Regards.
Ilona

0 Sudha kp over 8 years ago in reply to Ilona

Prodigy 50 points

HI Ilona,

We are doing some capacitor change at the input power supply op TPS65150 and monitoring.

We start to burn in from last Friday and I would continue to burn in the unit with this change for 1 week. If no issues I will let inform you next Monday about the status.

Regards,
Sudha

0 Ilona over 8 years ago in reply to Sudha kp

TI__Expert 8010 points

Hello Sudha,

Thanks for the update!

Best Regards.
Ilona

0 Ilona over 7 years ago in reply to Ilona

TI__Expert 8010 points

Hello Sudha,

Could you give us a short feedback whether the additional input capacitors have solved the problem?

Thank you.
Best Regards.
Ilona

0 Sudha kp over 7 years ago in reply to Ilona

Prodigy 50 points

Hi Ilona,

With the additional cap the system is stable and no more heating up issue.

You can close this case

Thanks for your support.

Regards,

Sudha

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TPS65150: Devices shutsdown at longer distance between LCD & driver