UCC2813 soft start issue

Trong Le

Hi team,

Below is the question from a customer regarding soft start time of UCC2813-4-Q1. Pls help to answer.

"We are testing UCC2813-4-Q1 and do not observe the soft start function. PWM duty goes directly from 0% to almost 50% during start up.
Any suggestions on how to further validate the soft start function of this PWM?"

Thanks,
Trong Le

over 10 years ago

0 Alexander Scheuermann over 10 years ago

TI__Genius 14890 points

Trong,

I will take a look at your question and should get back to you with a response on Monday. Thanks.

0 Alexander Scheuermann over 10 years ago in reply to Alexander Scheuermann

TI__Genius 14890 points

Trong,

Can you tell me what the value of FB and VCC is during these measurements? I would say that the only parameter that is measured for production is the COMP rise time which is 4-10ms when FB=1.8V.

0 Trong Le over 10 years ago in reply to Alexander Scheuermann

TI__Intellectual 1595 points

Customer has found out the problem as Vcc was dipping below 8.5V causing UVLO on the controller.

Thanks Alex.

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UCC2813 soft start issue