TPS61199: Disabling LED string after start-up

Matt Calvo

Part Number: TPS61199

Hey LED Driver team,

I have a customer prototyping with the TPS61199 for a new project and they would like to be able to select different backlight configurations via GPIO and as such would like to use a GPIO to disable unused LED strings on command during run-time.

We can see in the device datasheet that for unused LED strings the IFB pin needs to be held low during start-up to disable the string but can the IFB pin also be pulled down after start-up to disable the string?

Best regards,

Matt Calvo

over 1 year ago

+1 Patrick Yao over 1 year ago

TI__Mastermind 29010 points

Hi Matt,

If you pull low the IFB during operation, the IC will trigger LED open protection and as a result, the corresponding channel will be disabled. But the output voltage will rise first and then drop to normal value after the IFBx is removed. So it is still recommended to tie unused IFB pins to GND before start up.

Patrick

0 Matt Calvo over 1 year ago in reply to Patrick Yao

TI__Genius 14245 points

Thanks for the reply Patrick!

I'll go ahead and pass this info along to the customer and will have them comment back on here directly with any follow-up questions they may have.

-Matt

+1 Patrick Yao over 1 year ago in reply to Matt Calvo

TI__Mastermind 29010 points

Hi Matt,

Noted, I will close this thread for now and if you have further questions, please reply directly and it will re-open again.

Patrick

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TPS61199: Disabling LED string after start-up