LM5143-Q1: replacing TPS40140 by LM5143-Q1 as four phase interleaved current source

Frank Behlert

Prodigy 195 points

Part Number: LM5143-Q1
Other Parts Discussed in Thread: TPS40140, LM5143,

Hi,

the TPS40140 is NRND, so I'm looking for alternatives. The LM5143 looks fine from my position (after manual reading).

The PWM controller should have

- a precise current sharing

- four phase interleaving

- possibilities to change the output during operation (by SS or Manipulation of FB)

Input/Output Parameters are 24...60Vin; 20...48Vout; 0.5...50A out

If it could be stable over this wide output range must be checked. So I started with a Simulation, based on the LM5143-1 model and parameters calculated with the quick start design tool.

The simulation run well as long as the output was fixed to 5Vout (FB1 at gnd). If I replace the gnd connection of FB1 and replace it by a voltage divider (90k/10k --> 6Vout) the simulation fails.

LO2 keeps low during switching and after SS reaching 0.6V the Output 2 was interrupted.

Qould this be a Problem of the model? I have'nt read that this Feature (interleaved with variable output voltage) is not implemented.

Usually I start such a development with a simulation and increase the funcuality step by step up to the final design (as near as possible). Thats why this is very important and

thanks in advance for some help...

Frank

over 6 years ago

0 Samuel Jaffe over 6 years ago

TI__Mastermind 25590 points

Frank,

Thank you for your in-depth analysis. Let me connect you with the product expert to address your questions. You will receive a reply in the next day or two.

-Sam

0 Harish K R over 6 years ago in reply to Samuel Jaffe

TI__Intellectual 2320 points

Hi Frank,

The electrical simulations are not yet enabled for LM5143-Q1 on WEBENCH.

Could you please let us know if you are referring to PSPICE models under "Tools & software" section of the product folder ?

Thanks & Regards,

Harish

0 Frank Behlert over 6 years ago in reply to Harish K R

Prodigy 195 points

Hi Harish,

I prefer to use pspice and I'm happy that TI Supports this by providing excellent pspice models...

In this case I did the usual: Tools&software --> spice model --> opening the Simulation files, first Simulation as startup check --> start to change it according final design.

I made the changes for interleaving, started with a fixed Output of 5V: OK ; than I connected FB1 with the voltage divider 90k/10k and LO2 keeps on ground.

Thats the current situation.

Thanks for the quick response...

Frank

0 Harish K R over 6 years ago in reply to Frank Behlert

TI__Intellectual 2320 points

Hi Frank,

Thanks for quick response. We will forward this to concerned SPICE model team to look into your query/issue.

Best Regards,
Harish

0 Ashis Mondal over 6 years ago in reply to Harish K R

TI__Prodigy 610 points

Hi Frank,

Could you please share the test bench with us so that we can look into it.

Best Regards,
Ashis

0 Frank Behlert over 6 years ago in reply to Ashis Mondal

Prodigy 195 points

Hi Ashis,

it's uploaded.

Hope you see the same effect.....

Thanks

Frank

0 Ashis Mondal over 6 years ago in reply to Frank Behlert

TI__Prodigy 610 points

Hi Frank,

We are unable to download the project ,could you please attach the project here.

Best Regards,
Ashis

0 Frank Behlert over 6 years ago in reply to Ashis Mondal

Prodigy 195 points

Hi Ashis,
no idea what went wrong, I've used the "insert Code, attach filer..." feature for uploading.

Anyway, to be sure I started again by scratch and changed according the quickstart-tool. I saw some differences, tuned the compensation values and got the results I would expect.
Sometime the model is a bit more sensitive than the real part, but at the moment my problem is solved.

Why COMP jumps from 1V to 2V if it reaches the regultion point and I see no Change in dutycycle is interresting, may be I come back with this after checking the eval boards...

Thanks so far
Frank

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LM5143-Q1: replacing TPS40140 by LM5143-Q1 as four phase interleaved current source