TPS7A39: TPS7A39 Simulation fails to converge when loaded

Roger Brooks

Part Number: TPS7A39

I have put together a simple bipolar power supply base on the application notes in the TPS7A39 datasheet.

The PSpice simulation works fine as long as the output is unloaded, but I would like to add components to the output to see how it will behave under load.

However, as soon as I add any loading components, the simulation fails to converge. The attached version of the project includes two resistors, R14 and R15, intended to load the regulator at approximately 70mA. The simulation runs fine without them, but fails to converge as shown.

What am I doing wrong?

bipolarbatterycharger-2023-11-10T17-12.zip

over 1 year ago

0 Stephen Ziel over 1 year ago

TI__Mastermind 35795 points

Hi Roger,

Can you send me the .LIB files that are associated with this design?

Thanks,

Stephen

0 Roger Brooks over 1 year ago in reply to Stephen Ziel

Prodigy 50 points

I‘ll have to look for them. I wasn‘t aware of using anything that wasn‘t included in PSpice for TI. In fact, I was able to define more than three probes, which shouldn‘t have been possible if the design used any third-party components.

0 Stephen Ziel over 1 year ago in reply to Roger Brooks

TI__Mastermind 35795 points

I'm using the full version of Cadence so I don't automatically have those libraries installed. It's always better if I have the libraries that you are using anyway, just in case something has accidentally changed or anything like that. Yes, please look for them and send them over, then I will run the simulation and try to help debug if possible.

Thanks,

Stephen

0 Roger Brooks over 1 year ago in reply to Stephen Ziel

Prodigy 50 points

The components appear to be in the attached library.

Thanks for your help!

0 Roger Brooks over 1 year ago in reply to Roger Brooks

Prodigy 50 points

My attempt to attach the OLB file failed.

I'm trying to attach it as a zipfile:

.breakout.zip

0 Stephen Ziel over 1 year ago in reply to Roger Brooks

TI__Mastermind 35795 points

Thanks Roger. I had just located the missing libraries on my local machine but they were placed in different directories than what your cache settings had indicated, which caused the confusion. I'm looking at the simulation now and I'll reply soon with some feedback.

Thanks,

Stephen

+1 Stephen Ziel over 1 year ago in reply to Stephen Ziel

TI__Mastermind 35795 points

Roger,

Try changing the speed setting and enabling autoconverge. Normally these legacy models come with autoconverge enabled so all I'm really doing is modifying the speed setting here. This works for me - let me know if you have any additional issues.

Go to:
PSpice - Edit simulation profile