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TLV27L1: Biphasic Signal Generation Problem

Intellectual 685 points

Replies: 7

Views: 112

Part Number: TLV27L1

Hello,

I have asked my question before in this form. Now I face the problem again. I feed square waves of the Opamp for both inputs and get biphasic signal. But I don't what it is happening then I lost negative cycle of my signal. So, the output signal turns to monophasic signal. -5V and 5V supply voltages are correctly feeding the IC.

I have erased my microcontroller for not feeding any signal of the opamp. Then I replaced it but the problem is still there.

In the output figures, yellow graph is inverting input of the opamp and green is noninverting input. The third figure is output of the opamp. Do you have any idea to solve the problem?

Thank you

 

  • Hello Alpaslan,

    There is lots of information in the previous thread.  I will do the one thing that was missing last time, I'll build this circuit and test it tomorrow. I will test the inputs one at a time (because that will be easier for me) , have you tried testing phase 1 and phase 2 separately? The unused phase input must be grounded. 

     

    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:

    Hi Ron,

    When I feed with pulses to non inverting input of the opamp and make it ground inverting input, I get 5V output signal (like a step function with 5V amplitude). Then, when I feed only inverting part and make it other ground, I get zero volt output. So, the problem same again.

  • In reply to Alpaslan Ersoz:

    Hi Ron,

    I solved the problem. -5V loop is lost on bottom side. So I fixed with jumping cables.

    Thank you very much,

  • In reply to Alpaslan Ersoz:

    Hi Ron,

    I have one more question. Can I control which phase is first in the output signal? For example, can I control cathodic first or anodic first biphasic signal?

    Thank you,

  • In reply to Alpaslan Ersoz:

    Alpaslan,

    Swap the phase 1 and phase 2 inputs or generate them in the opposite order to set which output polarity happens first.

    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:

    Thank you Ron!

    I have a couple questions after feeding the bipasic voltage signal to howland current pump. I will share in the other tread with same title one. Because my howland current pump circuit is in there. Can you check them out? 

    Thank you

  • In reply to Alpaslan Ersoz:

    Reply sent.

    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).