LM5115: Is there a LaPlace domain model available?

Christopher Richardson

Part Number: LM5115

Dear E2E,

I've built an SSPR with this controller, and it works well. But the control loop bandwidth is quite low, only around 1 kHz. The device itself has a novel mix of voltage mode, VIN feed-forward and current mode control. Do you have a Laplace model for the power stage? I'm looking for something I could put into MathCAD, evaluate graphically, and then determine the gain and phase needed for the compensator.

Thanks,

Chris

over 6 years ago

0 Samuel Jaffe over 6 years ago

TI__Mastermind 25590 points

Chris,

Unfortunately we don't have much in the way of models online. Let me ask around and get back to you about this.

-Sam

0 David Baba over 6 years ago

TI__Mastermind 33130 points

Hello Chris,

I put together a MathCAD file. Vslope in the file below is computed to the Down slope of the inductor current.

Sorry Edited. If you follow the guidelines in the LM5115 datasheet, you can assume adequate slope comp is added. For the Mcad file, this is equal to the down slope of the inductor current. I believe the results will be well correlated and will match.

I hope this helps?LM5115 SSPR CMC Rev1.xmcd

David Baba.

0 Christopher Richardson over 6 years ago in reply to David Baba

Intellectual 360 points

Hi David,

Great to hear from you! And of course, many thanks for the MathCAD file. I thought I was the only one left in the world still using that software...

I'll post some real network analyzer plots so you can see how close you are to real life.

Again, thanks,

Chris

Power management

Power management forum

LM5115: Is there a LaPlace domain model available?