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DRV8301: SH_x input resistance

Guenter Fettig
Intellectual 1540 points
Part Number: DRV8301

If measuring Voltage at SH_x pins, without switching ON power stage MOSFETs, Voltage level is not like expected.

Can we specify related SH_x input resistance with tolerance ?

What way leakage current is going that leads to this Voltage drop ?

  • 0
    TI__Mastermind 21805 points

    Hi Günter!

    There is a weak pull-down enabled (~2kohms) on GH_x to GND when the device is in shutdown to keep the MOSFETs OFF. If a voltage is present on SH_x, this voltage will leak into GH_x and then to GND through this path. There is an additional 2.5kohms path to PVDD.

    Bear in mind that the datasheet does state that there is an errata condition where if a voltage is applied on SH_X before the device is powered up there is the possibility that the DRV8301 will not power up. (page 24 of the datasheet)

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    TI__Intellectual 1540 points

    Are we able to categorize the range of current, flowing LS Vds sense path ?

    Operating condition: after power up, normal condition, no drive signals for power MOSFETs.

    Configuration used for status analysis of output power stage after power up.

    Thanks a lot !

  • 0 in reply to Guenter Fettig
    TI__Mastermind 21805 points

    Hi Günter,

    If I understand your question properly, you are asking about current flowing out of SL_x and SNx pins into the sense resistor?

    The SNx pin has a current output of 100uA maximum based on the datasheet, there is no similar spec for SL_x (although I would expect a similar range).

    Thanks,

    Matt