LM5022: TINA Simulation, Boost 12VDC->65VDC@1A

Marsh Cai

Part Number: LM5022

Hi Teams,

I want to build a boost power supply, converting +12V to +65VDC, max Iout 1A.

Webench recommends the LM5022. So I build the TINA simulation file. Everything is nice, except the output voltage cannot be regulated to 65V. According to the webench report, the FB voltage divider was set as 18.2k:360, and the ouput voltage is 61V.

Cause my target is 65V, so I modified the divider aiming to get a higher output. However, no matter by decreasing RFB1(200) or increasing RFB2(20k). The output was still at 61, and not going higher any further.

On the contrary, getting a lower output can be easily achieved by decreasing RFB2 or increasing RFB1.

Can you kindly help to solve this problem?

The .TSC file is attached.

Thanks and BRs.

Marsh.

over 2 years ago

0 Harry Hofner over 2 years ago

TI__Genius 15795 points

Hello Marsh,

Thanks for reaching out to us via e2e.

I will have a look at it and come back to you within the next few days.

Best regards,

Harry

0 Harry Hofner over 2 years ago in reply to Harry Hofner

TI__Genius 15795 points

Hello Marsh,

So far I can confirm that we can reproduce the behavior here and that a modification of various parameters (e.g. input voltage, switching frequency etc.) does also not help to get above about 61V.

My colleagues are having a closer look now to find an explanation.

Thanks and regards,

Harry

0 Marsh Cai over 2 years ago in reply to Harry Hofner

TI__Intellectual 2365 points

Hi Harry,

Thanks so much for your and your colleagues' help.

Do we have any progress?

Marsh

0 Harry Hofner over 2 years ago in reply to Marsh Cai

TI__Genius 15795 points

Hello Marsh,

I am sorry to keep you waiting.

As I mentioned before we can reproduce the behavior of TINA but I could not get an explanation why this happens.
To be honest, TINA is more or less outdated and I am not sure how much support I can still get for it.

Therefore we have tried running the same model in PSpice for TI.
We have changed the voltage divider to turn the output voltage up to 70V and found that everything works fine in PSpice.

So I would recommend that you download PSpice for TI from our website and use this instead of TINA.
As you surely know, also our customers can download PSpice for TI for no charge.

Best regards,
Harry

0 Marsh Cai over 2 years ago in reply to Harry Hofner

TI__Intellectual 2365 points

Hi Harry,

Thanks for your reply. Can you kindly share this PSpice simulation file with me?

Thanks.

0 Harry Hofner over 2 years ago in reply to Marsh Cai

TI__Genius 15795 points

Hello Marsh,

I am sure that we can provide you with that.

The colleague who has the PSpice project working on his laptop is out today.

I will ask him on Monday to forward it.

Best regards,
Harry

0 Harry Hofner over 2 years ago in reply to Harry Hofner

TI__Genius 15795 points

Hello Marsh,

Attached please find the folder with the PSpice project that is using the part values of your TINA model.

You can find the PSpice Model that we have used on our website: https://www.ti.com/product/LM5022#design-tools-simulation

Filename: LM5022 PSpice Transient Model (Rev. B)

Best regards,
Harry

LM5022.zip

Power management

Power management forum

LM5022: TINA Simulation, Boost 12VDC->65VDC@1A