LM5045: Simulation Issue with LM5045 Circuit & not able to get output

Sonika .

Part Number: LM5045

Tool/software:

Hi,

I am Sonika, a Hardware Engineer at Applied Electro Magnetics Pvt. Ltd. I am currently simulating the LM5045 circuit as provided in the datasheet. However, I am facing an issue where the simulation takes a long time and the output is incorrect—I am unable to achieve the expected 3.3V output, despite using the same component values.

Additionally, I noticed that the example circuit for simulation on your website shows a non-isolated ground. For our application, and also according to the datasheet we require isolation between input and output grounds.

Kindly assist in resolving this issue.

Best regards,
Sonika

3 months ago

0 Hong Huang 3 months ago

TI__Guru 74115 points

Hi,

Please provide details of your simulation - simulation model, simulation circuit, etc. Simulation is ok conducted by connecting the primary and secondary-side ground connected to save time and simplify the simulation.

0 Sonika . 3 months ago in reply to Hong Huang

Prodigy 180 points

Hi,

I'm sharing the simulation circuit along with the library. Please let me know if there's anything else you need or if any additional requirements come up.

Best regards,
SonikaLM5045.zip

0 Hong Huang 3 months ago in reply to Sonika .

TI__Guru 74115 points

Hi,

I will have a look and will let you know if I need anything else.

0 Hong Huang 3 months ago in reply to Hong Huang

TI__Guru 74115 points

Hi,

Is LM5045.opj the one you are referring? If not please specify which one.

If yes, please provide simulation of the voltage on U17 pin 3 and pin 2 a long with Vout change in your simulation waveforms.

Please check the switching waveforms to see if normal.

0 Hong Huang 3 months ago in reply to Hong Huang

TI__Guru 74115 points

Hi,

I tried but your model LM5045.opj could not run on PSpice for TI, and shows a lot of errors.

0 Sonika . 3 months ago in reply to Hong Huang

Prodigy 180 points

Hi,

Yes, I'm referring to the LM5045.opj file. I'm observing a negative output voltage. I've attached waveform captures for the output voltage, as well as U17 pins 2 and pin3, along with the switching waveform.

I'm using the LM5045 model available in the PSpice library.

Best Regards,

Sonika

4621.Waveform.pdf

0 Hong Huang 3 months ago in reply to Sonika .

TI__Guru 74115 points

Hi,

It looks the negative voltage at the beginning. Is it due to the capacitor has a negative initial value.

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LM5045: Simulation Issue with LM5045 Circuit & not able to get output