TPS63021: Confirmation request regarding simulation waveform of PG output

Hi  Shinichi,

Could you attach your simulation schematic here?

Reagrds

Tao

Hi Tao,

Thank you for your reply.

The question is about the simulated waveform you attached.
I believe you created the simulation circuit.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1322139/tps63021-vout-voltage-when-pg-output-becomes-low-impedance

Could you please answer from the customer?

I appreciate your great help and cooperation.

Best regards,

Shinichi

Hi  Shinichi,

I am afraid i did not save the former simulation files. 

①What kind of connection of the PG terminal was used in the simulation?
Is it pulled up? What is its resistance value?　etc.

it is an open-drain structure, but not sure the exact resistance of FET internal.  but according the spec in DS, would like say typical resistance is 4KOhm.

Regards

Tao

Hi Tao,

Thank you for your reply.

Does that mean you most likely used the TPS63021's open-drain internal pull-up (approximately 4kΩ) in your simulation?

If so, what are the possible reasons for attached waveform above, when L⇒H, it rises steeply, and when H⇒L, it falls slowly. (square red flame)?

Does it make sense?

I appreciate your great help and cooperation.

Best regards,

Shinichi

Hi  Shinichi,

Do not know what happened internal. but i an just sure it is an open drain structure for PG.

Sorry for that. it is really an old device and actually i have encrypted model only, so i sm not sure what actually happened. 

Only resonable explanation should be the source and sink capability for diver of PG FET is not same in simulation model. But honestly, i think it should not happen. 

Regards

Tao

Hi Tao,

Is PG open drain?
Or is it push-pull?

Could you please run a simulation with the pull-up resistor(1MΩ) listed in the data sheet ?

If the results are the same, the customer can understand that the PG source/sink simulation model is not appropriate.

I appreciate your great help and cooperation.

Best regards,

Shinichi

Hi  Shinichi,

Please check the simulation sch and waveform below. yes, we got same behavior.

Regards

Tao

Hi tao,

Thank you for your reply and running a simulation.

I'll share the simulation result with the customer.

On the other hand, could you please answer whether the PG is open drain or push-pull?

I appreciate your great help and cooperation.

Best regards,

Shinichi

Hi Tao,

Thank you for your reply.

The customer wants additional information.

Could you please advise?

The customer is in a hurry.
Please provide your answers by April 25th (Thursday).

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(1) Is there any document you can provide regarding the internal circuit of TPS63021?
Could you provide more about it than the block diagram in the datasheet.

(2) If there is no detailed block diagram for the TPS63021,
Could you please provide the peripheral circuit of the PG terminal open drain circuit.

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I appreciate your great help and cooperation.

Best regards,

Shinichi

Hi Tao,

Thank you for your reply.

I'll send to the customer with the following information.

ｰｰｰ

There is no detailed block diagram other than the one in the datasheet.

Regarding the PG circuit, there is no detailed information other than the data sheet stating that it is open drain.

ｰｰｰ

When the customer has an additional question, I consult you again.

I appreciate your great help and cooperation.

Best regards,

Shinichi

Hi  Shinichi,

Thanks,  and sorry i could not give you a good enough answer for your questions. 

Regards

Tao

Hi Tao,

Thank you for reply.

I understand.

I sent your comment to the customer.

I appreciate your great help and cooperation.

Best regards,

Shinichi

Hi   Shinichi,

Thanks again. Do i need keep this thread open for your next feedback from customer?

Regards

Tao