WEBENCH® Tools/UCC2897A: https://www.ti.com/lit/tsc/slum606

MANOJ GUNDA

Part Number: UCC2897A
Other Parts Discussed in Thread: TL431

Tool/software: WEBENCH® Design Tools

I am trying to run simulation based on the model availabe on the TI website. In the given simulation of UCC2897A the output voltage considered is 3.3V.

I am trying to design forward clamp converter for 14V output. I relcalculated all the required values of resistor and capacitor values for required gains and compensation using the equations mentioned in the below link

But the output always settles at 3.3V. May i know what other changes i need to consider to simulate in TINA to get 14v at output.

over 3 years ago

0 Peter Meaney over 3 years ago

TI__Mastermind 31580 points

Have you change the restive divider feeding the TL431 reference and modified the transformer turns ratio?

Regards

Peter

0 MANOJ GUNDA over 3 years ago in reply to Peter Meaney

Prodigy 130 points

yes i have changed both of them even then output settles at 3.3V

0 MANOJ GUNDA over 3 years ago in reply to MANOJ GUNDA

Prodigy 130 points

slum606 - Copy.tsc UCC2897A_test.tsc

0 MANOJ GUNDA over 3 years ago in reply to MANOJ GUNDA

Prodigy 130 points

I have attached two links . slum606 -copy is the one with changed values. and UCC2897A- test with the one i completely changed . Please look into this for your reference

0 Peter Meaney over 3 years ago in reply to MANOJ GUNDA

TI__Mastermind 31580 points

Hi Manoj,

I am trying to simulate the file but taking a very long time to complete, how long are you waiting for the results on your setup?

Regards

Peter

0 MANOJ GUNDA over 3 years ago in reply to Peter Meaney

Prodigy 130 points

Hi Peter

Thanks for the response. I was looking for your response.

Slum6060 copy used to give result in a hour.

But the UCC2897A_ test takes a very long time more than 2 hours to get results.

I have made some changes to the simulation model. this is taking lesser time. but still, the result is not going above 3.3V.

please kindly look into this and help.UCC2897A_test_1.tsc

0 MANOJ GUNDA over 3 years ago in reply to MANOJ GUNDA

Prodigy 130 points

Hi peter

Any suggestions for the above issue.

looking for your support.

0 Peter Meaney over 3 years ago in reply to MANOJ GUNDA

TI__Mastermind 31580 points

Hi Manoj,

I modified the schematic for the 14V operation, I had to reduce the Current transformer burden resistor to 2R in addition to the transformer and output voltage potential divider.

I replaced the SR's with diodes to simplify the circuit but it stills crashes at about 80ms but you can see the output voltage approaching regulation.

I have attached the schematic and parameter file, if you go to and continue to adjust the parameters you should hopefully get the full circuit to simulate.

slum605_14V.TSC UCC2897a_14V.PRM

0 MANOJ GUNDA over 3 years ago in reply to Peter Meaney

Prodigy 130 points

Hi Peter

Thanks a lot for the simulation model. But i was unable to use parameter file. can you help me with how to access that parameter file.

0 Peter Meaney over 3 years ago in reply to MANOJ GUNDA

TI__Mastermind 31580 points

Hi Manoj,

Go to the Analysis tab, on the drop menu select Analysis Parameters and you will see the list of parameters available.

The ?Help button will take you to a description of each parameter setting.

Regards

Peter

0 MANOJ GUNDA over 3 years ago in reply to Peter Meaney

Prodigy 130 points

Hi peter

Thanks for the help. I was simulating with changing parameters. I removed current CT and replaced it with resistance in the ground path then again simulation is not good. Can you help me with this? why the result are changing by removing CT and replacing equivalent resistance.

0 MANOJ GUNDA over 3 years ago in reply to Peter Meaney

Prodigy 130 points

Hi peter

Thanks a lot for the suggestion. I am working on changing those parameters. I also made the following change to run the simulation.

I have removed the current transformer and replaced the equivalent resistor value at the ground side of the power MOSFET. But for the same simulation parameters the output results are changing can you please help me with this?

0 Peter Meaney over 3 years ago in reply to MANOJ GUNDA

TI__Mastermind 31580 points

Hi Manoj,

Can you be more specific when you say the output results are changing?

Please check that the voltage on the CS pin is the same value when you swap from the current transformer to the current sense resistor.

Regards

Peter

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WEBENCH® Tools/UCC2897A: https://www.ti.com/lit/tsc/slum606