TPS1641: Vcc reset - what are the timing requirements?

Lenio Cacula

Part Number: TPS1641

Tool/software:

My customer is using the TPS16412 and wanted to recover from a latch off condition using Vcc instead of EN/SHDN pin. The datasheet does not seem to cover this aspect - what are the requirements for switching off Vcc? Is it the same timing as EN/SHDN? What is the low voltage threshold?

In the customer's design, the fault occurs when the input voltage droops from 17V to about 7V and then back up to 17V. Right as the voltage begins to rise back up to 17V the fault line trips and stays tripped. This happens in roughly a 10ms transient. They are working to implement a patch to reset the device by cycling Vcc.

Thank you!

20 days ago

0 Amrit Jit 20 days ago

TI__Genius 11411 points

Hello Lenio,

Is VCC and VIN connected together or separately?

Thanks

Amrit

0 Lenio Cacula 20 days ago in reply to Amrit Jit

TI__Genius 16270 points

They are separate. What would change if they were connected?

0 Amrit Jit 18 days ago in reply to Lenio Cacula

TI__Genius 11411 points

Hello Lenio,

There is no data regarding Vcc recycling.

It's similar to power cycle but I can check on the EVM.

Can you tell me what customer wants to know ?

THanks

Amrit

0 Lenio Cacula 18 days ago in reply to Amrit Jit

TI__Genius 16270 points

Hi Amrit,

please proceed with the verification on the EVM. I am sending you customer information via email.

Thank you!

0 Amrit Jit 16 days ago in reply to Lenio Cacula

TI__Genius 11411 points

Hello lenio,

I will update results by tomorrow.

Thanks

Amrit

0 Lenio Cacula 15 days ago in reply to Amrit Jit

TI__Genius 16270 points

Amrit, were you able to run tests with the EVM? Thanks!

0 Amrit Jit 14 days ago in reply to Lenio Cacula

TI__Genius 11411 points

Hello Lenio,

Tested with VIN:8V

Keeping VCC below 6.5V turns off the FET and making it 7V turns ON the FET.

So, recycling can be done by keeping VCC below VIN by 2V and come back to VIN.

Thanks

Amrit

0 Lenio Cacula 14 days ago in reply to Amrit Jit

TI__Genius 16270 points

Amrit,

my original question was with regard to timing. I understand the voltage levels will reset the device, but what is the min time for it to take effect?

+1 Amrit Jit 13 days ago in reply to Lenio Cacula

TI__Genius 11411 points

Hello Lenio,

VCC delay is 500uSec.

Thanks

Amrit

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TPS1641: Vcc reset - what are the timing requirements?