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DRV8323: MOSFETS heating up with weird sound on the borad

Mahdi Ben Slimen
Prodigy 50 points
Part Number: DRV8323
Other Parts Discussed in Thread: CSD19506KCS

Hello, 

I'm using DRV8323 SPI version to command CSD19506KCS MOSFETS , with the following configuration: 

IDRIVEP_HS : 120 mA

IDRIVEN_HS : 240 mA

IDRIVEP_LS : 120 mA

IDRIVEN_LS : 240 mA

TDRIVE : 4000 nS

DEAD_TIME : 100 nS

VDS_LVL : 0.45V

and I left the rest of the config in default.

When I start the motor (with a low duty cycle), it works, but the FETs starts heating with a weird sound on the board (ticking).

And if I use a different config (or if I increase the duty cycle) I get GDF and VGS_Hx Faults !

There are figures of my HW : 

Is there any problem with my HW/SW configuration ?  

Thank you!

  • 0
    TI__Mastermind 26046 points

    HI Mahdi,

    Thank you for posting to the MD forum!

    Are all of the VGS_Hx faults occuring or is it happening on a specific phase? If you know which phase the fault is occurring on, can you measure that phase's GHx-SHx, SLx-GND, and nFAULT on the same scope capture? What is the voltage and current of the application?

    You may want to use the same IDRIVE setting for IDRIVEP_HS and IDRIVEP_LS, and the same IDRIVE setting for IDRIVEN_HS and IDRIVEN_LS. 

    As far as schematic, the caps and component choices look decent and I don't see any major issues. VM-VCP cap is rated at 100V, which is a little overkill because charge pump voltage is only VM + 10V.

  • 0 in reply to Aaron Barrera
    Prodigy 50 points

    Hello Aaron,

    Thank you for your response, 

    No, I don't get all VGS_Hx faults at the same time! It's not on a specific phase, sometimes I get this fault on phase A, another time on phase B or C.

    I measured GHx-SHx and I got 0V when INHx is logic low, and 12V when INHx is logic High.

    For SLx-GND always 0V.

    Regards,

  • 0 in reply to Mahdi Ben Slimen
    TI__Mastermind 26046 points

    Hello Mahdi,

    I apologize, I meant to say GLx-GND.

    If you have a scope, could you capture nFAULT going low at the same time with GHx-SHx and GLx-GND? Seeing the gate switching waveform when nFAULT occurs (goes low) will help provide details as to what is occurring when the VGS fault occurs. 

    Ensure nFAULT has a pullup resistor to accurately detect nFAULT going low.