TPS61196: LED current setting issue

NObody

Expert 1100 points

Part Number: TPS61196

Dear Sirs：

Customer used 98KΩ(RISET) connect ISET pin to GND, base on equation the LED current should be 50mA.

We think this setting is correct because TPS61196 LED current range is 50~400mA.

Actually, TPS61196 don't work when we set RISET = 98KΩ.

Any fault in this operation?

BTW, what value of resister is correct when we want to set LED current to be 50mA?

over 8 years ago

0 Caryss Li over 8 years ago

TI__Expert 4550 points

Hi ,
What is the failure mode? Have you changed the Riset to small lower value to see if the the driver works? And could you please check other connections like resistor connect to IFBx pins , that will affect startup unused pin detection.

0 NObody over 8 years ago in reply to Caryss Li

Expert 1100 points

We change RISET to 37.4KΩ and TPS61196 work normally.

Fault pin alway low when we power on TPS61196(RISET is 98KΩ. )

All connections are checked and no mistake.

As above, we think RISET value is only element that let TPS61196 don't work.

0 Caryss Li over 8 years ago in reply to NObody

TI__Expert 4550 points

I have a quick test on EVM, RISET =98K ohm is workable, and output current is 50mA as expected. SO 98K ohm is good to use.
I would suggest you to double check connections.

0 NObody over 8 years ago in reply to Caryss Li

Expert 1100 points

Hi, Caress：

I will check about it again and check it on EVM too.

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TPS61196: LED current setting issue