• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 78 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

CSD18543Q3A: Switching Loss Calculations

Thrinesh S
Prodigy 80 points
Part Number: CSD18543Q3A

Tool/software:

Hi,

For input 8V - 28V and output 3.3@10A. Planning to use LM5141RGET clubbed with CSD18543Q3A high side and low side fet. We need to calculate switching loss for the n-mos CSD18543Q3A[High + low side]. What rise time and fall times need to be considered ?. Is it the Tr and Tf of driver VGS or the fet VDS?. Also, the driver current requirement will be given by Idriver= Qg[Total gate charge]/Ttransition. Now, for the "Ttransition". What is the value to be considered?.

  • 0
    TI__Mastermind 38480 points

    Hello Thrinesh,

    Thanks for your interest in TI FETs. TI has a number of Excel-based FET selection tools including a synchronous buck tool which can be downloaded at the link below. I have also taken the liberty to prefill the attached spreadsheet based on your requirements. I started with the highest input voltage, 28V, as that will allow you to select the CSD18543Q3A from the pulldown list. Unfortunately, for the minimum input voltage, 8V, the tool will not include 60V FETs in the pulldown list. You can simply enter 8V input voltage and NOT click on the big blue button to see the calculated power loss estimates. The calculations tabs will show the detailed breakdown of power losses including switching loss. The switching loss calculations include the effect of common source inductance on the losses in the high side FET, Please let know if you have any problems with the spreadsheet or if you have any additional questions.

    https://www.ti.com/tool/SYNC-BUCK-FET-LOSS-CALC

    6180.SYNC-BUCK-FET-LOSS-CALC_Rev2.01.xlsm

    Best Regards,

    John Wallace

    TI FET Applications

  • 0 in reply to John Wallace1
    TI__Mastermind 38480 points

    Hi Thrinesh,

    Following up to see if your issue has been resolved. Please let me know if I can be of further assistance.

    Thanks,

    John

  • 0 in reply to John Wallace1
    TI__Mastermind 38480 points

    Hi Thrinesh,

    Thanks again for your interest in TI FETs. Since I have not gotten a response, I assume your issue is resolved and will close this thread.

    Best Regards,

    John