Tool/software:
We are currently working with the BQ7791506PWR battery protection IC and performing the Short Circuit Detection (SCD) test. However, we are facing an issue where the LD pin pulls low after some duration, even though the short is still present at P- and P+. This causes the IC to re-detect the short, turn off the MOSFETs, and enter a loop.
As a result, within one second, the MOSFETs are getting damaged due to continuous switching. We have captured waveforms where:
- Yellow represents Gate-to-Source voltage of the DSG FET
- Blue represents LD pin voltage
Observations:
- The MOSFETs are recovering and turning on despite the short still being present.
- The IC enters a loop where it detects the short, turns off the MOSFETs, and then recovers them again.This rapid switching is leading to MOSFET failure.
in this image we only captured the turnoff but not LOOP..
but in this second image, we captured the fet voltage in blue here You can see continuous switching..
