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TPA6120A2: Overcurrent

Kum Hoo Lee
Expert 1855 points
Part Number: TPA6120A2

Dear Sir/Madam,

I am using TPA6120A2 to do some test, +/-10V input, I am trying to make a switch from 2x gain to 6x gain for the amplifier. During the moment i switched from 2x gain to 6x gain, the IC drawn 100mA (norm should be less than 15mA). May I know why this will happen? And under what condition or circumstances, the amp will drawn such a high current? Will it be internal short?

Hope to hear from you soon.

Thanks and best regards,

KH

  • 0
    TI__Guru* 95285 points
    Hi KH,

    Could you share your schematic so we can take a look?
    This device has a relatively high offset voltage (it is not enhanced for pop performance), perhaps something is loading this offset voltage and so causing a current consumption higher than expected.
    You can email me at: ivan.salazar@ti.com

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    Expert 1855 points
    Dear Ivan,

    Thanks for your help. The schematic is not ready yet, because this is just in the testing and proof of concept phase. I just pull the audio signal to L/R IN+ and L/R IN-, with +/-10.8V into the IC and connect to headphone in this test.

    From you statement below, does it means that it might be the source that cause this issue? How can I prevent this? Beside this, is there any condition will make this amp drawn high current?
    “perhaps something is loading this offset voltage and so causing a current consumption higher than expected.”

    Hope to hear from you soon.
    KH
  • 0 in reply to Kum Hoo Lee
    TI__Guru* 95285 points
    KH,

    Is my understanding correct that you are using some kind of external switch that changes the input/feedback resistors in order to change the gain?
    One thing you could try to identify if increased current consumption is caused by external circuitry is to make two different circuits, one for 2x gain and other for 6x gain, not using the switch.

    Regarding what I said in my last post, it could be, are you connecting a load or headphones to the outputs of the TPA6120A2 when you test it?

    Best regards,
    -ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    Expert 1855 points
    Hi Ivan,

    The amp is connected to a 24 Ohms headphone.

    And I have tried just either change the resistor to 2X or 6X gain without the switch, the high current still happened, and is only when I play around the with headphone connector then I see high current.

    Any idea why this will happen?

    Thanks and best regards,
    KH