Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 3 answers
  • Subscribers 64 subscribers
  • Views 1873 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.

Original question:

UCC21530: Pspice simulation error

UCC21530: Use to handle a H-bridge in simulation pspice

user6220518
Prodigy 40 points
Part Number: UCC21530

Hi,

I am trying to handle a H-bridge with 2 UCC21530, however, when I try to simulate the UCC21530 it only works if both VSSA and VSSB are referenced to the same ground.

I need to manage a N-chanel Mosfet one for each chanel of UCC21530, but if VSSA=VSSB the load will be short-circuited.

  • 0
    TI__Prodigy 650 points

    Hello,

    Thank you for your question. I work on the applications team in the high power drivers group.

    Looking at your schematic your bootstrap diode (Cboot) is smaller than we recommend and may not be able to charge up fast enough when switching on the high side. I’d recommend lowering it to a few uF (2.2uF).

    If this answered your question, could you please press the green button? If not, feel free to ask more questions.

    Thanks and best regards,

    Zach                                                                                                                                                                                   

    All information in this correspondence and in any related correspondence is provided “as is” and “with all faults”, and is subject to TI’s Important Notice (http://www.ti.com/corp/docs/legal/important-notice.shtml).

  • 0 in reply to Zachary Wellen
    Prodigy 40 points

    Hi Zach,

    I tried using a small Cboot, (2nF and 22nF), however it still not working. I could make it work by using on independent source VDD between VDDA-Vssa and other between VDDB-VssB. It seems like the Cboot do not have ground so it could not be charge, except ground is connected to VSSA.

    I am using Orcad Capture CIS version 17.2 2016.

    However, in LTspice program, it works perfectly.

    Did you notice some issue with Orcad Capture CIS version?

    Thanks for your help

    Héctor

  • 0 in reply to user6220518
    TI__Prodigy 650 points

    Hello Héctor,

    I’m glad you got your simulation working.  I seem to have mistyped before but a bootstrap capacitor of 2.2uF should be sufficient.

    I’m not familiar with any issues with our models in OrCAD Capture CIS?  If you want you can link your simulation files and I can take a look at them.

    Thanks and best regards,

    Zach

  • 0 in reply to Zachary Wellen
    Prodigy 40 points

    Hi Zach,

    Find the circuit in the attachment.

    Thanks again

    Héctor

    H_bridge.zip

  • 0 in reply to user6220518
    Prodigy 40 points

    Hi Zach,

    Sorry, I finally found the problem, my fault, I did not use the right Diode DBoot it does not support enough reverse voltage), I have replaced it and now it works perfectly.

    Thanks for your help

    Héctor

  • 0 in reply to user6220518
    TI__Prodigy 650 points

    Hi Héctor,

    Thank you for sending me your design files.  The issue turned out to be Dboot.  The breakdown voltage was too low and resulted in the supply voltage on VSSA to drop below UVLO threshold.  Replacing it with an ideal diode fixed the issue and resulted in the waveform I’ve attached.  It takes a few cycles to charge up the bootstrap capacitor and once VSSA passed the UVLO threshold there is still 50us of delay till the output will turn on.

    If this answered your question, could you please press the green button? If not, feel free to ask more questions.

    Thanks and best regards,

    Zach