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DRV8718-Q1: Offline Diagnostic

Ivy Jin
Expert 4625 points
Part Number: DRV8718-Q1

Tool/software:

Hi team,

May I know that in the DRV8718-Q1 offline diagnosis, is the current source in the figure a common current source? 

The customer used GH1/GH3/GH5/GH7, and the customer found that as long as there was one short circuit to ground on the high side of a load, the over-voltage faults of all four VDS were set 1. So they want to make sure that if the internal current source is common source.

Regards,

Ivy

Ivy

  • 0
    TI__Mastermind 44855 points

    Hi Ivy,

    Thank you for your question. Could you use internal E2E when you attach some internal document etc?

    With high side load and SHx GND short condition should be like followings. Then SHx =GND, therefore comparator of high sides are all 1.

    regards

    Shinya

  • 0 in reply to Shinya Morita
    TI__Expert 4625 points

    Hi Shinya,

    Thanks for your comments.

    Perhaps I didn't describe it clearly enough, the following figure is the customer's actual short circuit test scenario.

    Under such circumstances, what is the potential reason for this issue? 

    Regards,

    Ivy

  • 0 in reply to Ivy Jin
    TI__Mastermind 44855 points

    Hi Ivy,

    Thank you for your question.

    - With this GND short condition, VDS over current protection should work while driving output. So external FET should be protected. No issue.

    -This GND short cannot be detected by Offline diagnastic.  Because Motor load is connected to GND already by motor itself. If motor resistance is 1ohm, OUTPUT already has 1ohm to GND path as DC.

    regards

    Shinya