TINA/Spice/LM3481: Simulation Oddities When Replicating SEPIC Eval

Kevin Schmidgall

Part Number: LM3481
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Howdy,

I am using the LM3481 Transient Model. As a test I wanted to replicate the LM3481 SEPIC Eval board (SNVA461A) but the results I'm getting are strange when I try with a load step. Once the load step occurs, the output voltage decreases to around 8.3V (from 12Vn) and never recovers. I am attaching the TINA file and transient results.

LM3481 - TINA.TSC

over 8 years ago

0 ranjanir over 8 years ago

TI__Intellectual 1760 points

Hi Kevin

I am not sure i understand what you are trying to do correctly. there already is a macro for you on the product folder and the load transient TINA-TI design for you to view the simulation successfully. I think there might be some issue with how the pins might be mapped in your macro that you have created but you can run the load transient by making changes to the following file.

snvm229b.TSC

Thanks

Ranjani

0 Britt Brooks - Online Design Tools over 8 years ago

TI__Mastermind 41310 points

Kevin,

Please take a look at this possible solution for your circuit. I have changed the implementation to use the transformer in TINA-TI and added a leakage inductance of 200n.

LM3481 - TINA_sepic.TSC

Here is the example I created previously:

LM3481_sepic.TSC