TPS92640: start up issue with low analog dimming

Ryo Akashi

Expert 8960 points

Part Number: TPS92640

Hello experts,

I got question about start up with low analog dimming from customer.

My customer can't start up well when they set low analog dimming.

In datasheet P14, I found the discription related with proper start up as below;

Vcs should be greater than 10mV.

Also, in equation (4), Vcs is defines as Viadj/10.

Is this possible to be related with low analog dimming?

I'm sorry I'm not clear about relation between Vcs and low analog dimming.

I would appreciate if you would give me advice.

Thanks and best regards,

Ryo Akashi

over 4 years ago

0 Irwin Nederbragt over 4 years ago

TI__Mastermind 28655 points

Hello Ryo,

Have they implemented the offset resistor as described in the datasheet?

What are the steps they are taking and when does the issue arise? Are they dimming down via Iadj until the LEDs extinguish?

Best Regards,

0 Irwin Nederbragt over 4 years ago in reply to Irwin Nederbragt

TI__Mastermind 28655 points

Hello Ryo,

I haven’t heard back from you, I’m assuming you were able to resolve your issue.
If not, just post a reply below (or create a new thread if the thread has locked due to time-out)

Best Regards,

0 Ryo Akashi over 4 years ago in reply to Irwin Nederbragt

TI__Expert 8960 points

Hello Irwin-san,

I'm sorry for my late reply.

I am confirming with customer, let me ask later.

Sorry for making you wait.

Thanks and best regards,

Ryo Akashi

0 Irwin Nederbragt over 4 years ago in reply to Ryo Akashi

TI__Mastermind 28655 points

Hello Ryo,

I'm going to close this since we are working on this issue via email.

Best Regards,

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TPS92640: start up issue with low analog dimming