• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 62 subscribers
  • Views 209 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.

BQ76952: Higher side DSG FET failure

Kushal Pal Singh
Prodigy 30 points
Part Number: BQ76952


Tool/software:

Hi team,

We are using BQ76952 with higher side FET, We are observing FET failure during MOSFTE turn off .

MOSFET fall time seems high and we also observed ringing at Vds 

Please check below schematics & waveform of Vgs, Vds & Current.

  • 0
    TI__Mastermind 18795 points

    Hello Kushal,

    Please give me some time to review the schematic. Can you share your procedure or what you were trying to test when this occurs? Or is this just a general observation?

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Prodigy 30 points

    Hi Alex_H 

    Thank you for your reply
    We are testing OCD protections, rated current is 100A.

    We are observing this during DSG FET turn off when current is >100A.

  • 0 in reply to Kushal Pal Singh
    TI__Mastermind 18795 points

    Hello Kushal,

    • From the waveform you shared regarding the ‘ringing’, do you mind sharing a waveform of the DSG pin, the FET’s gate voltage, PACK+, and BAT+ voltage as well?
    • When the FET driver turns-off for the BQ76952 device, the device will initially begin discharging the DSG pin toward VSS, however, it will stop the discharge if the DSG pin voltage drops below the LD pin voltage. This repeats in a series of pulses to help protect the DSG FET from excessive negative gate-source voltage. Further information regarding this can be found in Section 16.5 FET Driver Turn-Off from the datasheet, including some waveforms to show it.
    • Can you also share which OCD protection you are using and what configuration you have set it to? (OCD 1, OCD2, or OCD3, Threshold, fault delay, etc.)

    Best Regards,
    Alexis