[TPS7A4001] About output capacitor capacity and the relation of electric discharge time.

Satoshi

Guru 19645 points

Please let me know the expression of relations of time (time to fall to 0Vout) to carry out the completion of electric discharge with output capacitor capacity when power supply(Vin) OFF is carried out.

※Or when 1 μF is placed, in what sec does it fall to 0Vout?

Since it assumes carrying out power supply ON/OFF to early timing at customers, it cares about such spec.

(It has told recommending 4.7 μF or more currently written to the data sheet.

It consents as my having you think as reference data less than it. ）

Input and output are the following.
30Vin=>5Vout/～10mA

Thank you for your consideration.

over 12 years ago

0 Kartik Sinha over 12 years ago

TI__Expert 3300 points

I will confirm this and get back to you early next week. Thanks

Regards,

Kartik

0 Satoshi over 12 years ago in reply to Kartik Sinha

Guru 19645 points

Dear Kartik-san

Thank you for your reply,I understood.

Reply pleasure of a later is used.

best regards,

Satoshi

0 Satoshi over 12 years ago in reply to Satoshi

Guru 19645 points

Dear Kartik-san

How are the affair and situation about which it consulted the other day?

Since a customer is contacted if time is likely to be taken a little longer, please let me know.

Best Regards,

Satoshi

0 Kartik Sinha over 12 years ago in reply to Satoshi

TI__Expert 3300 points

Satoshi-san,

We have finished taking data for you. Please refer to the below scope plot. I have replicated your customer's setup on the bench and captured turn off time for this device. As you can see it takes ~18ms for Vout to get from 5V to 0V with a 10uF output cap. It is highly recommended to use 10uF at the output, with 1uF output will not be stable. Please let me know how I can help further.

Regards,

Kartik

0 Satoshi over 12 years ago in reply to Kartik Sinha

Guru 19645 points

Dear Kartik-san

When not having carried out correspondence of high-speed discharge in peripheral circuitry, how many seconds is discharge time?

I think that it takes 2～3seconds at 4.7μF.

Please let me know 1μF of discharge time, and a formula.

Best regard,

Satoshi

0 Kartik Sinha over 12 years ago in reply to Satoshi

TI__Expert 3300 points

Satoshi-san,

I will try to get this again.

Regards,

Kartik

0 Satoshi over 12 years ago in reply to Kartik Sinha

Guru 19645 points

Dear Kartik-san

Thank you for the correspondence.

Two days after the customer, when he wanted the reply, the request was.

It will be saved if it teaches in the range to understand.

Regards

Satoshi

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[TPS7A4001] About output capacitor capacity and the relation of electric discharge time.