DRV8332: Leakage current from PVDD

Hi Daisuke,

This seems consistent with specs from the datasheet. The spec IPVDD_X (PVDD idle current) is what you're measuring, and in the datasheet it is 0.7mA typical per half bridge at 400kHz PWM frequency and PVDD = 50V. Since this is a much lower PVDD value, the leakage current should be less than 0.7mA per half bridge. 

Unfortunately we don't have characteristic curves for IPVDD vs. PVDD, so I cannot confirm the correct value for IPVDD_X when PVDD is 12V but the lower value is consistent with my expectations. 

Thanks,
Aaron

Hi Higa-san

Yes, PVDD is voltage supply for each half-bridge and is powered by outside. It should not be connected to GND. We do not have leakage current specs for this scenario. 

Thanks,
Aaron

For PVDD to be connected to GND? The only way this could occur is if there is an internal shoot-through current in the Integrated FETs, which should be mitigated if the PCB is well designed without added inductance in the OUT_x paths. Since there's not a current path for OUT_x, there should be no current paths for current to flow so this should not impact gate switching in the driver. There is also a small dead time inserted between HS and LS FETs, so there should be no risk of shoot through current. 

If anything, overcurrent protection should protect the device in shoot through conditions and Hi-Z the FETs internally - which means the only leakage current paths are the PVDD paths already measured. 

Thanks,
Aaron

Hi Higa-san,

Yes, you are correct, this is the correct leakage current path out of PVDD. There should be no other leakage current paths since the bootstrap capacitors provide the gate drive current and there are no other dependencies on PVDD.

Thanks,
Aaron

Hi Daisuke-san,

I found the DRV8312EVM today in lab, but I did not get time to test today. I will perform the test first thing on Monday in lab and provide you a result on Monday. 

Thanks,
Aaron

Hi Daisuke-san,

I captured about 1.2mA coming from PVDD to GND due to GVDD = 12V. 

Thanks,
Aaron

Hi Daisuke-san,

I was only able to measure the current using a DMM out of the PVDD pin on the EVM. It is likely coming from PVDD_x (0.4mA each phase's PVDD pin), but I cannot measure each current specifically on the EVM. I do not have bench capabilities either to test specific pins. 

I found an old thread that exactly replicate what the customer is asking: https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/307780/drv8332---leak-current-from-vdd-gvdd-pin-to-pvdd-pin

Since there is no power shutdown sequence in the datasheet, the leakage current can be removed in the following ways:

- Removing GVDD before PVDD
- Setting RESET_x = 1 and PWM_x = 0 to mask the leakage current

Thanks,
Aaron