Hello team,
We are facing an issue with the DRV8353H IC in one of our converter. Below are the observations.
1. Based on various drive settings, the motor spins till certain duty cycle and then suddenly out of nowhere, DVDD goes down to 1.8 V
2. No external circuits are powered with the DVDD. Just a bypass capacitor of 1 uF, 25 V is used.
3. With a drive setting of 50/100 mA, the motor runs in OL, NL till 10-13 % duty cycle and suddenly DVDD gets loaded and goes to 1.8 V, further to which, the IC gets heated slowly
4. With a drive setting of 300/600 mA, the motor runs in OL, NL till 40-60 % duty cycle and suddenly DVDD gets loaded and goes to 1.8 V, further to which, the IC gets heated slowly. Further increase in gate driver setting leads to damage of the driver as it exceeds the dv/dt rating of the IC based on FET gate charge (5.2 nC)
5. We checked if the bypass capacitor is damaged, but that is fine.
6. Also, we ran the motor with a dyno and different RPMs and based on the hall sensor feedback, observed the open pole voltages (Motor unconnected) obtained at various duty cycles. The driver works perfectly fine in this case.
7. All the shunt resistors and DC current sense resistor is also bypassed to validate the ground shift related problems. Still DVDD loads to 1.8 V
8. All the other voltages VM, Enable, PWM, Hall sensors voltages are stiff during and after fault. DVDD going low is the initiation point of the fault. As core voltage goes below 1.8 V, it doesn't even report fault!
Nothing helped us in resolving the reported issue.
We are confused on how to proceed. Can someone please guide us? Your help would mean a lot to us. Please advise.
I have attached the capture of the wave forms for your perusal. The noise overriding is due to ground wires.
Thanks,
Siri
