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TLV9061-Q1: Request for schematic design review

Jeffrey Chung1
Expert 2745 points
Part Number: TLV9061-Q1
Other Parts Discussed in Thread: TLV9061

Tool/software:

Hi Team,

Please review this schematic design below and let me know the points that should be modified. There are the current sensing specification in the attachment.

TLV9061-Q1_Schematic.pdf

Regards,

  • 0
    TI__Mastermind 26981 points

    Hey Jeffrey,

    A couple notes. You have listed your gain as 200, however, since there is no resistance on VOFFSET#1, your gain would be 201. Please note that if you do want to add an offset on VOFFSET#1, you will need to make the parallel combination of R90 and R91 equal to 200k. Alternatively, you can simply attach a 200k resistor and place a buffer amplifier between the 200k resistor and the R91/R90 voltage divider.

    I would not include C37 as configured as this will degrade your phase margin. If you must include differential filtering, I would split R60 and R63 into two 500Ohm resistors and place C37 in between them.

    Also, are you trying to sense current accurately near 0A? If so, you may need to add a small offset on Voffset to bring the op amp output common mode range within the linear range of the output stage. The amplifier's region of high aol is 50mV from either rail.

    Best,
    Jerry

  • 0 in reply to Jerry Madalvanos
    Expert 2745 points

    Hi Jerry,

    Thanks for your kind response. Let me check it with customer and answer you about your question.

    Regards,

  • 0 in reply to Jerry Madalvanos
    Expert 2745 points

    Hi Jerry,

    Customer modified their schematic based on your comments. Voffset voltage will be supplied to 50mV. Please review the modified version.TLV9061-Q1_Schematic_2nd.pdf

    Regards,

  • +1 in reply to Jeffrey Chung1
    TI__Mastermind 26981 points

    Hey Jeffrey

    The voltage generated from Voffset is going to cause issues with gain error, and will be sinking a lot of current (~10mA). The best way to implement this is shown below. This accomplishes the comment from my first response.

    Jerry Madalvanos said:
    Please note that if you do want to add an offset on VOFFSET#1, you will need to make the parallel combination of R90 and R91 equal to 200k

    Best,
    Jerry

  • 0 in reply to Jerry Madalvanos
    Expert 2745 points

    Hi Jerry,

    Thanks for your 2nd review. Let me check your feedback with customer and ask you if they have more questions.

    Regards,