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DRV8353RS-EVM: 0X400 FAULT

user5177722
Prodigy 90 points
Part Number: DRV8353RS-EVM
Other Parts Discussed in Thread: DRV8353,

Hi,

We are using DRV8353RS-EVM module for testing our BLDC motor.  But today we are faced with a nfault condition. We saw the error in the picture below. Also, the DRV8353 temperature is too high. What is the cause of this problem? How can I fix?

  • 0
    TI__Mastermind 18900 points

    Hello ,

    Your image didn't load so I'm not sure which fault we could be talking about. The fault status registers have explicit names and help give more info for what fault was triggered.

    Making some assumptions, 0x04 lines up with the VDS OCP or VGS faults, assuming 0x04 is signifying the bit that is triggering, which both indicate something has happening with the FETs. Usually high temperatures mixed with VDS faults mean there's a lot of current flowing through the FETs which indicates damage. Can you determine which fault corresponds to which FET or phase do some basic impedance checks on the FETs and the gate driver pin (e.g. GHA) and see if the test was damaged? 

    If you didn't take a look at the gate source and sink current and adjust or verify the values match the EVM (i.e. not used the highest value), then there's a good chance the board was damaged. Please review this post if you don't know how to match gate drive current to a FET

     

    Best,

    -Cole

  • 0 in reply to Cole Macias
    Prodigy 90 points

    Dear Cole,  

    Fault code is 0x400  and  Drv8353rs is too hot.  Is that same with Fet problem?   Fault bit is Logic or registering fault, I think it is not about aFet but I will check again.  IS  there anything else i should check?

  • 0 in reply to user5177722
    TI__Mastermind 18900 points

    Hello ,

    The gate drive faults specifically check if, after trying to turn the driver on or off, that the driver is on and off by using VGS monitors, and if trying to turn on the FETs, too much current is running through them (as if the FET was damaged and the RDSon is now replaced with a short), then it will trigger a fault using the VDS monitors. This is how the DRV checks if the FETs are damaged. This criteria is explained in the fault table within the datasheet.

    To your point, a hot DRV usually means the damage occurred at the DRV. Please check the gate pins, GLx and GHx impedance to GND and VGLS.  If this the case, then its a 90% chance that too high of IDRIVE caused spikes that damaged the DRV and I'd encourage you to read the IDRIVE blog post I gave in the previous post.

    Best,

    -Cole