• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 1483 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM5035: Simulating using LTspice

Jeroen Nonnekes
Prodigy 50 points
Part Number: LM5035

Hello TI,

I am using the LM5035 lib directly in ltspice. With the dutycylce ramped to the maximum for testing and simulation purpose.

The problem as for now is that the IC seems te restart every 1ms, we cannot see how the ic would shutdown with all the protection circuits disabled for the simulations.

Does anyone know what makes this IC shutdown and recover in this manner?

The LtSpice results we got:

  • 0
    TI__Genius 13660 points

    Hi Jeroen, 

    From the block diagram in the page 11 of the datasheet, only UVLO, OVP, VCC/VREF UVLO faults and thermal limit (165C) will cause REF drop to 0V, then restart.

    In the simulation, UVLO, OVP and thermal limit are good. So we need continue to check VCC pin and REF pin, the VCC pin is good in my side.

    I recommend trying to add a 0.1uF capacitor at REF pin and  remove the current source between REF and COMP, and then I would to pull the COMP pin to ref or leave it open circuit to command max duty cycle.

    Regards,

    Teng

  • 0 in reply to Teng Feng
    Prodigy 50 points

    Hello Teng,

    Thank you very much this was much help. the controller seems to want to keep working now.

    but it wont reach its potential due to oscilations in the HO signal. HO wont keep the mosfet open for the whole duration. it looks like an 1.2-1.3 Mhz sine oscilation. anything you know that would help?

    Kind regards,

    Jeroen

  • 0 in reply to Jeroen Nonnekes
    TI__Genius 13660 points

    Hi Jeroen,

    The Cgs of Mosfet looks quiet large in the simulation, please check the model of MOSFET.

    What I often will do is that first remove the power stage, then to see if LM5035 works well.  If it is good, then it should be due to power stage especially MOSFET model.

    Regards,

    Teng