TPS54525: Soft start time

Darren Chang

Part Number: TPS54525

Hi Expert,

My IPC customer would like to confirm the adjustment range (min and max values) for the soft start capacitor of TPS54525 and If exceeds the designated value, will it have any impact on the IC?

Currently, they are considering changing from 8.2nF to either 4.7nF or 2.2nF in the design.

Thank you.

Darren

5 months ago

+1 Lucia Gao 5 months ago

TI__Mastermind 18110 points

Hi Darren,

If customer chooses 4.7nF, the soft start time would be 0.65ms. With 8.2nF, the soft start time would be 1.15ms. Do you see a reason why they would like to lower the SS time?

Actually the SS time will have an influence on inrush current. Please kindly according to below equation:

Thanks!

BRs

Lucia

0 Darren Chang 5 months ago in reply to Lucia Gao

TI__Expert 4120 points

Hi Lucia,

Because Apacer SSD request voltage rise time can’t over 1ms.

Thank you.

Darren

0 Lucia Gao 5 months ago in reply to Darren Chang

TI__Mastermind 18110 points

Hi Darren,

Got you, thank you.

BRs

Lucia

0 Darren Chang 5 months ago in reply to Lucia Gao

TI__Expert 4120 points

Hi Lucia,

From my understanding, it is okay to limit the soft-start time to less than 1ms, but customers need to evaluate whether the inrush current is within the over-current range and whether the input voltage drop caused by the inrush current is acceptable. Am I right?

Thank you.

Darren

+1 Lucia Gao 5 months ago in reply to Darren Chang

TI__Mastermind 18110 points

Yes, you are correct.

Thanks!

BRs

Lucia

0 Darren Chang 5 months ago in reply to Lucia Gao

TI__Expert 4120 points

Hi Lucia,

Thanks very much!

Darren

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TPS54525: Soft start time