TINA/Spice/LP87524B-Q1: Part II

Kazuhiko Hirano

Genius 15088 points

Part Number: LP87524B-Q1
Other Parts Discussed in Thread: TINA-TI, LP87524-Q1

Tool/software: TINA-TI or Spice Models

Hello,

My customer is simulating LP87524-Q1 PSPICE model LP87524B-Q1_TRANS.LIB.

He would like to het 0.93V/1A output at channel #2, but he is not able to get expected results.

Please take a look at the attached simulation circuit and results, and please advise what is wrong.

Best regards,

K.Hirano

over 6 years ago

0 Nick Jakse49 over 6 years ago

TI__Expert 4155 points

Kazuhiko,

Can you try using a constant voltage for the NRST input?

Our device expert should get back to you soon, but in the meantime that is something I noticed that I think could be causing your issue.

0 Kazuhiko Hirano over 6 years ago in reply to Nick Jakse49

TI__Genius 15088 points

Nick,

Thank you for your feedback.

My customer already tried constant high voltage for NRST pin.

Since he was not able to get the expected results, he changed from constant voltage to pulse, low to high after power up.

But it does not make any changes on the results.

Anyway, I look forward to hearing further feedback from the device expert.

Best regards,

K.Hirano

0 Jari Niemela13 over 6 years ago in reply to Kazuhiko Hirano

TI__Genius 13850 points

Hi Hirano-san,

There seems to be something working differently on your simulations with LTspice than with my simulation with Cadence Pspice.

Have your tried to connect external components also for BUCK1? I would suggest to do so. And also enable other rails by setting EN_BUCKx voltage sources to 1.

On my simulations behavior is a little bit different with all 4 BUCKs enabled than only with 1 BUCK starting. Anyhow on my simulations device is starting likewise your simulations BUCK output never reach regulation.

0 Jari Niemela13 over 6 years ago in reply to Jari Niemela13

TI__Genius 13850 points

Hi Hirano-san,

Any success with simulation? Were customer able to get around the issue?

0 Kazuhiko Hirano over 6 years ago in reply to Jari Niemela13

TI__Genius 15088 points

Jari,

I am still awaiting customer’s response.

Please wait for a while.

Best regards,

K.Hirano

0 Kazuhiko Hirano over 6 years ago in reply to Kazuhiko Hirano

TI__Genius 15088 points

Jari,

My customer enabled all four channels and put the same loads for them.

Then, they get an error, “time step too small”, this time.

They do not know how to change the “time step”.

Anyway, why the simulation does not work correctly when just one channel is enabled?

Since they did not get the time step error when they simulated one channel, can TI fix the issue by modifying the simulation model so that it works correctly when just one channel is enabled?

Best regards,

K.Hirano