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DRV8353R: DRV8353RSRGZT

Yesaiahu Redler
Intellectual 490 points
Part Number: DRV8353R

Dear TI engineer.

In order to prevent a short situation between the VDRAIN, VM and the VIN signals inside the DRV8353RS component.

Are they completely separated by a different chips. Can you elaborate about the separation of the gate drivers and the power supply section.

Best Regards

Shaya

  • 0
    TI__Mastermind 26416 points

    Hi Shaya,


    Thank you for your question! I will try to get back to you tomorrow with an answer.

    Regards,

    Anthony 

  • 0
    TI__Mastermind 26416 points

    Hi Shaya,

    I have attached a PDF outlining the ways that VM, VDRAIN, and VIN interacts with the rest of the device. In addition, it is important to ensure that the voltages remain below the absolute maximum ratings of the device to prevent any damage internally to the driver. if the abs. max ratings are exceeded, then there is a risk of internal shorting in the device. As long as you stay within the ratings of the device you shouldn't have any problems with internal shorting. 

    Please let me know if you have any further questions.


    Regards,

    Anthony 

    DRV8323RS Voltage Isolation.pdf

  • 0 in reply to Anthony Lodi
    Intellectual 490 points

    Thanks Antony

    I will convey your PDF to TUV. they have mentioned this issue hopefully they will except it.
    Another issue is the VCP as a single point that have to feed 3 gate drivers
    how you ensure that a voltage difference in the source pins of the external transistors will not discharge the VCP charge pool for the other gate drivers below the required VGS?

    Best Regards

    Shaya

  • 0 in reply to Yesaiahu Redler
    TI__Mastermind 26416 points

    Hi Shaya, 

    VCP is a voltage that is 10.5V higher than VM, so if VM is 24V then VCP would be around 34.5V. When the driver provides a command to turn on one or multiple of the high side gates, this voltage is then applied to the gates of the MOSFETs that are commanded to turn on.  So the same voltage of VM+10.5V would be applied to all the high side gates of the MOSFETs that are supposed to turn on (in our example, 34.5V), regardless of whether or not there are some slight variations in the source voltages. This guarantees that the VGS will be at least around 10.5V above the source voltage, enabling the MOSFETs to fully turn on. 

    Please let me know if you need any further help or clarification.

    Regards,

    Anthony

  • 0 in reply to Anthony Lodi
    Intellectual 490 points

    Hi Antony

    TUV SUD ask for more information about the safety requirements for STO approval.
    The require information Is:

    1 what is the precaution made by TI to prevent a short between VM,VDRAIN and Vin inside the chip.

    2 written document about the safety level that insure that such a short circuit can't happened.

    I am sure that TI safety group have such information, Can you guide me how to reach it?

  • 0 in reply to Yesaiahu Redler
    TI__Mastermind 18900 points

    Hello Yesaiahu,

    By the way, we have a Functional Safety quality managed version of the device (unfortunately without the buck, as they were wildly unpopular. note the datasheet update for this change is in progress) that you can explore: https://www.ti.com/product/DRV8353F

    Here's a app note on: Implementing STO functionality w/ diagnostic and monitoring for ind. motor drive and here's some documentation about TI's safety nomenclature: https://www.ti.com/technologies/functional-safety/overview.html#commitment

    If you don't find what you're looking for there. Let us know.

    Best,

    -Cole