TPS2124: Soft Start Cap

KrnB

Part Number: TPS2124

Tool/software:

Hello,

Datasheet states typ switchover time of 100us but also mentioned dependence on Soft-Start if Second Source becomes valid & is selected as Output.

I want fast switchover, Please share what is the lowest Cap value possible for Css to have fastest Slew Rate? Can the Css pin be kept floating (without external cap) for fastest Slew Rate ?

For holdup capacitance calculation I am considering Typ 100us Switchover time & not considering Soft-Start time (Slew Rate). Is this understanding correct?

5 months ago

0 Patrick Shalton 4 months ago

TI__Mastermind 21325 points

Hi KrnB,

The 100us switchover time is from when the device disconnects VIN1 to VIN2 and vise versa, so that will still be within 100us either way. However, the initiation of that switchover will be delayed when switching to the second source.

Thanks,

Patrick

0 KrnB 4 months ago in reply to Patrick Shalton

Intellectual 580 points

Thank you for the reply !

Please share what is the lowest Cap value possible for Css to have fastest Slew Rate & lowest settling time delay? Can the Css pin be kept floating (without external cap) for fastest Slew Rate of output & lowest settling time of inputs?

0 Patrick Shalton 4 months ago in reply to KrnB

TI__Mastermind 21325 points

Hi KrnB,

Apologies for missing that part - yes, the fastest slew rate and settling time is with the SS pin floating.

Thanks,

Patrick

0 KrnB 4 months ago in reply to Patrick Shalton

Intellectual 580 points

Thank you for the reply.

Please can help to confirm approximate Slew Rate when SS pin floating.

0 Patrick Shalton 4 months ago in reply to KrnB

TI__Mastermind 21325 points

Hi KrnB,

This should be around 40kV/s (5V/125us) as an estimation.

Thanks,

Patrick

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TPS2124: Soft Start Cap