TPS63051: About Soft Start issue

Tsukui Yusuke

Guru 21930 points

Part Number: TPS63051

Hi,

Let's talk about the soft start and output voltage of the TPS63051.
Customers are testing SS caps in the 10nF and 22nF patterns.
In that test, the output voltage waveform started up while oscillating.
Let me ask you two questions in this background.

１．Could you tell me the reason why the output voltage starts up after oscillating?
２．What is the maximum recommended capacity of SS capacitors?

And I want to share the customer's waveform with you.
Could you let me share the waveform with a private message?

Regards,
Yusuke

over 3 years ago

0 Brigitte over 3 years ago

TI__Guru 59445 points

Hello Yusuke,

The effectiveness of capacitors in the range of 10nF or more is very limited. Please have a look at the attached measurements with a startup with 1nF and 101nF.

TPS63050 startup.pptx

For private communication, please use the friendship request in E2E.

0 Jasper Li over 3 years ago

TI__Mastermind 46905 points

Hi Yusuke,

I request friendship with you. please accept and share the waveform with me. i will support the questions in the future.

0 Tsukui Yusuke over 3 years ago in reply to Jasper Li

Guru 21930 points

Hi Brigitte and Li,

Thank you for your kind response.

I sent the waveform to Li.
Would you please check the materials you shared?
Please answer again for 1 and 2.

Best regards,
Yusuke

0 Jasper Li over 3 years ago in reply to Tsukui Yusuke

TI__Mastermind 46905 points

Yusuke,

1. i don't know which oscillation do you refer to, there is no oscillation in the material Brigitte shared. and i didn't receive your waveform

2. there is not limitation on this capacitor. the 10n and 20nF customer used is acceptable.

0 Tsukui Yusuke over 3 years ago in reply to Jasper Li

Guru 21930 points

Hi Li,

Thank you for your response.

As a result of confirming the load conditions with the customer
It was almost no load condition.
Is there any other possible cause?

Regards,
Yusuke

0 Jasper Li over 3 years ago in reply to Tsukui Yusuke

TI__Mastermind 46905 points

Hi Yusuke,

let's communicate through private message and close the post to save our time. thanks!

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TPS63051: About Soft Start issue