DRV8320: GDF fault condition confirmation

Part Number: DRV8320

Hi team,

Customer want to know if GDF is triggered uder gate current is OFF, but motor externally rotating, then current flows via diode of H/L side MOSFET.

Please let me know. best regards, ny

over 3 years ago

0 Aaron Barrera over 3 years ago

TI__Mastermind 26046 points

Hi NY,

When a GDF fault occurs, all external MOSFETs are Hi-Z. Any current that is in the motor when rotating will flow through the external FET's body diodes up to the supply.

Thanks,
Aaron

0 NY over 3 years ago in reply to Aaron Barrera

TI__Expert 3040 points

Hi Aaron,

Thank you very much for your answer.

Is there a possibility that a GDF fault will occur when the gate voltage of Hside and Lside is both in the L state?

0 Anthony Lodi over 3 years ago in reply to NY

TI__Mastermind 27596 points

Hi NY,

The way a GDF occurs is when an input (INHx or INLx for 6x PWM mode) goes high to turn on a MOSFET, but the GHx to SHx voltage fails to turn on by the end of the tDRIVE time. If this occurs, then a GDF is reported to indicate that the MOSFET failed to turn on. The GHx to SHx voltage must be above around 2V for the DRV to consider the MOSFET on. You can check out section 8.3.6.5 of the datasheet for information on the GDF feature.

Regards,

Anthony Lodi

0 NY over 3 years ago in reply to Anthony Lodi

TI__Expert 3040 points

OK thanks!

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DRV8320: GDF fault condition confirmation