TINA/Spice/UCC28070: UCC28070 question about TINA-TI Transient Reference Design（slum328).

Bob Lee62837

Mastermind 7230 points

Part Number: UCC28070
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Dear support member,

My customer used UCC28070.

I have a question about UCC28070 TINA-TI Transient Reference Design（slum328).

In this circuit model, the output current is 0.75A (max).
I want to simulate as 7A under the specification conditions.

(Question)
Where should I change when operating with a load of 7 A as a UCC28070 simulation circuit(slum328)?

Best regard.
Bob Lee.

over 6 years ago

0 John Griffin1 over 6 years ago

TI__Mastermind 34465 points

Hello Bob,
You should change the load resistance RLOAD from 531 Ohms to 57 Ohms.
This will provide for a 7A load current
Regards
John

0 Bob Lee62837 over 6 years ago in reply to John Griffin1

Mastermind 7230 points

Dear John Griffin1,

Thank you very much for reply.

The RLOAD constants were changed.
The simulation does not show that the input current waveform is a sine waveform.
Is it PFC operating normally?

Best regard.
Bob Lee.

0 Bob Lee62837 over 6 years ago in reply to Bob Lee62837

Mastermind 7230 points

Dear John Griffin1,

Could you teach progress situation?

Best regard.
Bob Lee.

0 John Griffin1 over 6 years ago in reply to Bob Lee62837

TI__Mastermind 34465 points

Hi Bob Lee,
I have asked one of the simulation to review and respond to you.
He should be able to solve this issue soon.
Regards
John

0 Bob Lee62837 over 6 years ago in reply to John Griffin1

Mastermind 7230 points

Dear John Griffin1,

Thank you very much for support.
When can you answer me?

Can you answer by Japan time May/24th?

Best regard.
Bob Lee.

0 Saket over 6 years ago in reply to Bob Lee62837

TI__Intellectual 2680 points

Hi Bob,

It seems that the model is validated for maximum 0.75A. This is mentioned in TINA application schematic. So, I am not sure if model can support 7A load current.

Regarding your query "The simulation does not show that the input current waveform is a sine waveform.
Is it PFC operating normally?"

The model is derived from average model of UCC28070. It is an approximated transient model and we will not able observed sinusoidal waveform for input current.
You will observe average value and not exactly transient behavior.This is a kind of limitation of this model.

0 Bob Lee62837 over 6 years ago in reply to Saket

Mastermind 7230 points

Dear Saket,

Thank you very much for reply.

May I ask a add question?

Your answer was that " It is an approximated transient model and we will not able observed sinusoidal waveform for input current. "

Question1
What is there any way to observed sinusoidal waveform for input current?

Question2
Is there TINA-file?

Question3
Can it check observed sinusoidal waveform for input current on the PSpice Model?

Best regard.
Bob Lee.

0 Saket over 6 years ago in reply to Bob Lee62837

TI__Intellectual 2680 points

Hi Bob,

Regarding your question 1, the answer is No and Pspice and TINA model both should give same results.

As it is derived from average model the response will be like the one you are getting in simulation results.

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TINA/Spice/UCC28070: UCC28070 question about TINA-TI Transient Reference Design（slum328).