• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 40 subscribers
  • Views 528 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.

TIDA-00449: Protection FET Selection

JPAlleyne
Expert 1565 points
Part Number: TIDA-00449
Other Parts Discussed in Thread: CSD19536KTT

I’m currently looking at the TIDA-00449 http://www.ti.com/lit/ug/tiduar8b/tiduar8b.pdf . On page 5/36 section 4.1.3.1 FET Selection, I saw that the designer chose to use two CSD19536KTT in parallel on each FET driver (CHG DSG). I reviewed the datasheet for the FET and I was wondering which spec influenced the engineer to use two in parallel? And would his design be outside of spec if he just used one FET.

  • 0
    TI__Intellectual 2850 points
    In the TIDA-00449, the FETs were selected to fit both the voltage and the current requirements, as explain in the section 4.1.3.1.
    In this case it was designed for 10 cells in series and up to 50A of continuous discharged current.

    When the FETs are closed (when no fault occurred), the FETs will have to dissipate the power lost across their RDson. So in the TIDA-00449, two FETs were used in order to share the losses and be able to withstand the 50A of discharge current.

    For lower current applications, using a single FET for the CHG and one for the DSG is not a problem, as long as you make sure that they can withstand the current that passes through them.

    It is the same reason that three sense resistors are being used in parallel (see section 4.1.2)