LM74912-Q1: FLTn start-up behavior

Vincent den Boer

Prodigy 10 points

Part Number: LM74912-Q1

Tool/software:

Hello,

I have 3 questions.

What is the state of the FLTn with EN being in low state?
Can I use the FLTn pin to enable the LM74912-Q1?
What is the start-up behavior of the FLTn pin?

4 months ago

0 Shiven Dhir 4 months ago

TI__Mastermind 46370 points

Hi Vincent,

1. When EN is low, FLTb will be held high due to pullup.

2. No, FLTb is an output pin of controller and cannot enable controller.

3. Startup behavior of FLTb depends on pull-up reference.

FLTb is pulled low only in the following cases.

Regards,

Shiven Dhir

0 Vincent den Boer 4 months ago in reply to Shiven Dhir

Prodigy 10 points

Hi Shiven,

Thank you for your response!

Since FLTb is high due to the used pull-up, it could be used to enable the controller as well, right? When a fault occurs, the signal will be pulled low and disable the controller.

My concern is that this will create some kind of loop of fault -> disable -> enable (due to the pull-up) -> fault, etc...

0 Shiven Dhir 4 months ago in reply to Vincent den Boer

TI__Mastermind 46370 points

Hi Vincent,

Yes, it may create a loop. But the idea of using FLTb to enable another controller is not bad.

Regards,

Shiven Dhir

0 Vincent den Boer 4 months ago in reply to Shiven Dhir

Prodigy 10 points

Would it also loop if the FLT situation is cleared? Is the FLTb status faster then the enabling of Vout? (see image below)

+1 Shiven Dhir 4 months ago in reply to Vincent den Boer

TI__Mastermind 46370 points

Hi Vincent,

Yes, FLT status if faster

Regards,

Shiven Dhir

Power management

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LM74912-Q1: FLTn start-up behavior