UCC28C40: SMPS: 85V - 265V AC to 13.8V DC

Dhruv .

Prodigy 10 points

Part Number: UCC28C40

Tool/software:

Dear sir,

I want to stimulate SMPS circuit on LtSpice and TINA TI but facing some issues.

1. On LTSpice, the IC UCC28C40 is not working even after providing the biasing voltage. I have enclosed the same.

2. On Tina TI the stimulation results are very different from the desired outcome i.e., the aux will not able to generate any voltage. I have enclosed the same.

Not only this if I remove the aux and use only primary and secondary winding only the circuit is operating partially.

7 months ago

0 Hong Huang 7 months ago

TI__Guru 73575 points

Hi,

We do not support LTSpice

Please provide your TINA TI simulation file.

0 Dhruv . 7 months ago in reply to Hong Huang

Prodigy 10 points

Hi,

MINI_electro in TINA TI _with_new_transformer.TSC

I have attached the TINA TI stimulation file for the reference.

0 Hong Huang 7 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

What are your assumed output voltage and AUX voltage?

0 Hong Huang 7 months ago in reply to Hong Huang

TI__Guru 73575 points

Hi,

I created a new circuit based on your circuit and a workable circuit. Attached. It works normal. You can modify the attached circuit to your need one step at a time to find which step the circuit shows not working. Then find out why.

MINI_electro in TINA TI _with_new_HH.TSC

0 Dhruv . 7 months ago

Prodigy 10 points

I want to design my circuit for 110kHz switching freq. but this stimulation designed for different switching frequency. What should be the formula to get the desired values of R and C for my requirement

0 Hong Huang 7 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

Datasheet Fig 6-1 shows these.

0 Dhruv . 6 months ago

Prodigy 10 points

Sir, when i make changes in simulation file according to our need then the simulation does not work.

0 Hong Huang 6 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

Please provide your simulation file that worked before changes, and also describe what changes you did the the file became not working.

0 Dhruv . 5 months ago

Prodigy 10 points

Hi,

I made changes such as change the turns ratio, resistors and capacitor value according to my schematic and add the BJT in feedback section. I have attached the schematic file here.

MINI_electro in TINA TI _with_new_HH (6).TSC

0 Hong Huang 5 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

I cannot get your schematics from the link which is prohibited from accessing. Please attach your file instead of using the link.

0 Dhruv . 5 months ago in reply to Hong Huang

Prodigy 10 points

Hi,

I have attached the schematic for your reference. Can you help me to simulate the circuit according to my need as the spice model is not working in tina ti and also in lt spice

0 Hong Huang 5 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

No we do not help make simulation unless you get approval based on your business case.

You need to send your request to your TI sales office to help this process.

We can support your simulation related questions but not do the simulation for you unless approved.

0 Dhruv . 5 months ago in reply to Hong Huang

Prodigy 10 points

Hi,

Please let me know if i made changes according to my requirement then the simulation file provided by you would not work.

0 Hong Huang 5 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

I am not sure what you are asking. Please send your TSC file to me to help understand where to change.

0 Dhruv . 5 months ago in reply to Hong Huang

Prodigy 10 points

Hi,

I am asking that when i made changes in the TSC file according to my schematic requirement I am getting the wrong output (not getting the output voltage and the aux voltage) but hardware of the same circuit works fine.

On hardware the Vaux < 11 V and Vout = 13.8 V.

I have attached the .TSC file (reference file) and the schematic diagram for the reference

MINI_electro in TINA TI _with_new_HH (7).TSC

0 Hong Huang 5 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

If your simulation does not work the same way as your physical circuit, there maybe something not setup correctly on your simulation.

I found your schematics shows

R14 = 11k, but your simulation R4 = 15k,

R21 = 2.4k, but your simulation R5 = 3.9k.

After these two changes, Vout = 13.9V, very close to your hardware 13.8V.

Vaux is related also to the turns ratio Nas which is assumed but may not be the same as your physical.

So it looks not problems on the simulation circuit except you did not make them the same on the feedback resistors R14 and R21 to R4 and R5.

0 Dhruv . 5 months ago in reply to Hong Huang

Prodigy 10 points

Hi,

After making changes in simulation R4, R5, R7, R8, R1, C8, Turns ratio, Primary inductance, R11, C16 (according to schematic), I am getting decreasing aux voltage.

But it has to be like this, please help me to get the desired result.

0 Hong Huang 5 months ago in reply to Dhruv .

TI__Guru 73575 points

Hi,

Please provide a table to list component values before the change and after the change.

If only AUX decreasing compared to your physical circuit it can be due to the transformer model different from reality. The transformer model in the simulation is not a true real transformer. If you want to look into adjustment the transformer you need to compare to reality test to add parameters or ask the transformer vendor to provide the transformer PSpice model.

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UCC28C40: SMPS: 85V - 265V AC to 13.8V DC