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Original question:

AFE031: Power amplifier block

AFE031: Current driving capability

Radel Design Team
Intellectual 460 points
Part Number: AFE031


Hi,

We intend to use AFE031 for powerline communication.

When injecting a signal into power line using AFE031 and a coupling circuit, the output of the power amplifier reduces to 3Vpp from 6Vpp ( after LVCAP ). The transformer used is 1:1 ferrite cored having primary and secondary inductance of 300uH.

When tried to drive a inductive or resistive load directly from output of power amplifier, the amplifier is driving the current in order to maintain the voltage. But why is it not driving the current into power line?

regards

  • 0
    TI__Guru* 77541 points

    Hello Bharath,

    I need more information from your setup. Per your description, the PA from AFE031 side is working. I will look into possible coupling losses through transformers and/or IR losses. Please let me know the following:

    1. What is your AC power frequency? (Coupling circuit for a DC line is different from AC line). I assumed that you are running AC line since you are using transformer coupling. 

    2. What type of Ferrite Core are you using? Please give me the part number. 

    3.  What is driving current after the transformer? what is the load after the secondary? What is your LVCAP value?

    4. What frequency are you transmitting, CENELC A, B, C or D?

    Can you send me the schematic of your setup? A hand drawing will be ok as well.  I'd like to see the complete test configuration from primary to secondary of transformer including the load. 

    Regards,

    Raymond

  • 0 in reply to Raymond Zhang1
    TI__Guru* 77541 points

    Hello Bharath,

    Did you resolve your issues? If you need additional help, I can walk you through with the test setup. please let us know. 

    Regards,

    Raymond

  • 0
    Guru 140200 points

    Hi Bharath,

    have you read this appnote?

    Kai

  • 0 in reply to kai klaas69
    Intellectual 460 points

    Hi,

    Yes I have already gone through this application note.

    regards,

  • 0 in reply to Raymond Zhang1
    Intellectual 460 points

    Hi, thank you for the quick response.

    Below are the details required.

    1. What is your AC power frequency? (Coupling circuit for a DC line is different from AC line). I assumed that you are running AC line since you are using transformer coupling.

    The AC power frequency is 50Hz.

    2. What type of Ferrite Core are you using? Please give me the part number.

    We are using a customized Ferrite core that is available with us which doesn't have a generalized part number.

    3.  What is driving current after the transformer? what is the load after the secondary? What is your LVCAP value?

    The driving current is always less than 50mA.

    We connected a 100 ohms resistive load and then reduced it gradually to 12 ohms. As the load increased, the voltage across the secondary reduced and even the voltage at the primary also reduced slowly.

    The LVCAP we are using is 10uF.

    4. What frequency are you transmitting, CENELC A, B, C or D?

    The frequency  that we intend to use is 135kHz - 145kHz.

    I have attached a schematic of the coupling circuit for reference.

    Regards,20191112115853493(1).pdf

  • 0 in reply to Radel Design Team
    TI__Guru* 77541 points

    Hi Bharath,

    I replied your questions in Winword, and please see the attached file. 

    If you have additional questions, please continue to post them. I think that your issues are resolved for now. 

    Transformer Coupling Issues 11122019.docx

    Regards,

    Raymond

  • 0 in reply to Raymond Zhang1
    Intellectual 460 points

    Hi,

    Thank you for the quick response.

    This has helped us and we will get back to you, if we have any more queries.

    Regards,

  • 0 in reply to Radel Design Team
    TI__Guru* 77541 points

    Hi Bharath,

    I am going to close the inquiry. If you have other questions, you may open a new one and continue to post on this link.

    Best,

    Raymond