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DRV8305-Q1: DRV83055QPHPRQ1 current sense

Genius 4355 points
Part Number: DRV8305-Q1

Our customer has a question about the TI pre-driver: DRV83055QPHPRQ1.

On the board equipped with DRV83055QPHPRQ1 created in the past, the current detection accuracy becomes worse as the amount of current increases.
The reason is that the GND of the pre-driver and the GND of the microcontroller are different as shown in the attached (current).
(Because there is a GND potential difference, the detection accuracy deteriorates.)

Therefore, they are thinking of improving the accuracy of current detection by sharing the GND of the pre-driver and the microcontroller as shown in the attached(modify).
Is there any problem in using DRV83055QPHPRQ1?

DRV83055QPHPRQ1.xlsx

They shouldn't do this kind of modify ?

Please give us know your advise.

Regards,

Kura

  • Hi Kura-san,

    The issue is not in where the ground is connected to for the DRV8305-Q1, but rather how SGND and PGND are connected in the customer's layout. When using split grounds, it is imperative that there are low-inductance components (i.e. wide 0-ohm resistors, net ties, etc.) that tie the two grounds together while still separating them so that noise from motor switching does not couple into SGND. 



    If GND potential difference exists, it is recommended to optimize the grounding of the layout so PGND and SGND are sectioned off so that noise doesn't interfere with each other but also share the same potential. 


    Thanks,
    Aaron