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OPA172: OPA172 Output oscillation and False trigger OCP issue

Intellectual 1315 points

Replies: 2

Views: 152

Part Number: OPA172

Hi Guys

Our customer is using our opa172 as current sense. Please see below the schematic:

But when they use it test the output current, the OPA172 Amp's output will be noisy or oscillated at output 86A load. that will lead to false trigger OCP. But when they change another one OPA192. The output will be stable and will not trigger the COP any more. (OAP172 and OPA192 P2P replace and no other components change)

OPA172:      CH2:output current;CH3:output voltage;CH4:OP output(IC411 Pin 1)

OPA192:      CH2:output current;CH3:output voltage;CH4:OP output(IC411 Pin 1)

Your feedback are very appreciated.

Thanks

-Pengfei

  • Pengfei,

    Try removing C422; capacitors between the input pins of an op amp create more problems than they solve.

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

  • In reply to Ron Michallick:

    Vincent,

    Was the capacitor removal helpful or do you need further assistance?

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

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