List the following test items for the DRV8323 broken machine to find the cause of the damage. the total units run are 400pcs and the failed quantity is 12pcs.
Note: All broken devices are manifested as the G pole drive failure of the upper tube, and the waveforms produced by the damaged IC are all in the case of DIS_GDF = 1
1. Compare whether the resistance of the damaged IC pin has changed
Conclusion: Measure the relative resistance of CH, SH; GH, SH to 54V resistance; GH, SH to ground resistance, there is no significant difference
2. Compare whether there is a difference between IC pin and MOS pin waveform
Conclusion 1: Measure the relative resistance of CH, SH; GH, SH to 54V resistance; GH, SH to ground resistance, there is no significant difference
Conclusion 2: There is no significant difference between the waveform of the IC pin and the waveform of the MOS pin
Conclusion 3: The influence of the diode close to the IC and close to the MOS on the driving waveform is the same, the negative differential voltage at the MOS terminal is slightly larger than the negative differential voltage at the IC terminal
Conclusion 4: The GH current of the normal IC is the same as the software setting, the current of the bad IC rises but the voltage is not maintained
Conclusion 5: The VGS of a normal IC will continue to rise with the input power, and the VGS of a damaged IC will not continue to rise when it rises to 6.8V.
Conclusion 6: Diable Gate Drive Fault is to remove the protection, not only does not report an error, changing the T-drive can change the protection time
Conclusion 7: The VCP of the damaged IC has obvious fluctuations when switching, and the normal IC does not
Conclusion 8: Tested 20 different combinations did not work properly
And you can see the schmatic and test report as the following.