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TPA6132A2: How to control with a potential meter for TPA6132A2

yunsong sim
Intellectual 270 points
Part Number: TPA6132A2

TPA6132.DSN

Hi guys,

I am designing a personal monitoring system for band players with TPA6132A2.

I just want to know where I can put a potential meter for volume control.

I think input pin would be good so put it there, however, it doesn't work as I expected.

Here's my thought: you can two options for it.

Which one would be good and plz suggest the resister numbers for it because it would effect the input impedance as well.

Best regards

  • 0
    TI__Guru** 109145 points

    Hi Yunsong,

    You usually control the gain of an amplfiier by changing the input resistor or the feedback resistor, specifically for TPA6132A2 both of these resistors are integrated in the IC, using pins G0 and G1 to adjust those values.

    Based on that, if you want to add an external component to adjust the gain, you can try as below:

    • Place a series variable resistor between C9 and pin 8 of the device. This variable resistor will be in series with the internal input resistor, the larger it's value the lower the gain; and when the variable resistor is set close to 0ohm, the gain would be the one set by pins G0 and G1.
    • You follow a similar approach on C12 along with pin 10.

    The resistor divider as you suggest with R7 and R5 may work as well, although R5 would represent a power loss for the input signal, being a tradeoff of how the voltage divider works when R5 is a large value vs the power loss on this resistor when it's a small value.

    There are TINA and PSpice models available for this device, you may use these to estimate what would be the resulting signal.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Intellectual 270 points

    Thanks for your answer which is great for me.

    However, I have a problem to execute the-TI spice. PLZ check my circuit.

    Best regards,

  • 0 in reply to yunsong sim
    TI__Guru** 109145 points

    Hi Yunsong,

    I'll check the simulation later today or early tomorrow. If simulation has problems we can also check TINA instead.
    I'll share updates as soon as possible.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • +1 in reply to Ivan Salazar
    TI__Guru** 109145 points

    Hi Yunsong,

    Apologies for the delayed response, I'll check this today and provide further comments by the end of the day.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    TI__Guru** 109145 points

    Hi Yunsong,

    Please add the HPVSS decoupling cap, I think this is the only error in your simulation:

  • 0 in reply to Ivan Salazar
    Intellectual 270 points

    Thanks a lot!!! missed it..