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DRV8714-Q1: Offline Open Load and Short Circuit in driving Solenoids application

Jay wang
Expert 3191 points
Part Number: DRV8714-Q1

hi expert

customers are using DRV8714(BRG_MODE=11b) to drive solenoids/relay. the SCH is shown below(8714 will be as low-side switch).

additionally, i saw the following slides to show how to implement Offline Open Load and Short Circuit Implementation Example detection. but this slides is NOT for solenoids/relay Open Load and Short Circuit detection.

2313.DRV87xx-Q1_Offline_OL_SC_rev1.pdf

So my question is whether can VDS fault be applied in solenoids/relay Open Load and Short Circuit detection?

  • 0
    TI__Mastermind 44655 points

    Hi,

    Thank you for your questions.

    Yes,  off state diagnostic can be used for solenoids /relay as well. 

    Here is case Low side FET driving on SHx. 

    1) Normal/good case.

       It will be same as Battery short case on Page 6. 

       We can use 2 sequences "PU_SHx=1, PD_SHx=0" and "PU_SHx=0, PD_SHx=0" like bellow. Then VDS_Hx =1 and VDS_Lx =0 by sequence 1 and 2.

    2) GND short case

      We can use 2 sequences same as 1). Then has same result as page 5.

    3) Open case.

     We can use 2 sequences same as 1). Then has same result as page 4.

     

    Battery short circuit (page6) case cannot be detected. However this is not DRV's limitation, normally low side solenoid driver cannot detect battery short case.

     

    regards

    Shinya Morita

  • 0 in reply to Shinya Morita
    TI__Expert 3191 points

    hi Shinya

    thanks for you detailed comments.