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TPA2008D2: Transient Current when ShutDown

Shinichi Inoue
Guru 19941 points
Part Number: TPA2008D2

Dear  Specialists,

My customer is evaluating TPA2008D2 and encountering unexpected beeping noise at shutdown.

I would be grateful if you could advise.

---

When the device shuts down, the speaker makes a beeping sound.

It sounds like a different sound from the pop noise.

It tends to occur immediately after starting the device. It does not occur after a certain amount of time after power on TPA2008D2PWP.

At that time, when the device is shut down, the current consumption increased and the voltage of LDO dropped below 4.5V.

How much transient current does the TPA2008D2 flow when shutting down?

Block Diagram.pptx

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I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Guru* 98255 points

    Hi Shinichi,

    Can you get scope captures of the output during the transient? Or a recording of it?

    Could you also clarify on a couple things:

    • Does the sound happens only after power up? Never happening after that or during power down?
    • Beeping noise is repetitive or a single sound?
    • The current consumption is increased when shutting down? Is it only for a short period of time or sustained increased consumption?
    • Is it consuming more current in shutdown than active mode?
    • Can you also try with amplifier disconnected from it's input?

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Guru 19941 points

    Hi Ivan,

    Thank you for your reply.

    I send the information I have now.

    • Does the sound happens only after power up? Never happening after that or during power down?

    >This is happened power down.

    • Beeping noise is repetitive or a single sound?

    The noise occurred for 120ms after shut down signal input.

    • The current consumption is increased when shutting down? Is it only for a short period of time or sustained increased consumption?

    >Since the output voltage of the LDO drops at shutdown, the current consumption seems to increase momentarily in both normal and abnormal situations.
    When noise is generated, the output voltage of the LDO does not recover and remains low, so we believe that the current consumption will remain high.

    • Is it consuming more current in shutdown than active mode?

    >I don't have any information. I'll confirm the customer.

    • Can you also try with amplifier disconnected from it's input?

    >I'll confirm the customer.

    The customer'd like to communicate offline.

    So, could you please send a friendship request or e-mail address. 

    Then I'll send the waveform and others.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Guru* 98255 points

    Hi Shinichi,

    I've sent you a friendship request. Let's follow up with any shared files in private messaging.

    120ms seems pretty long time after shutdown, can you check the inputs of the amplifier during that time? Is there a chance some signal is coming to the inputs after shutdown? Ideally we should isolate the amplifier to diagnose if it's caused by the inputs, or from supply or other source.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Guru 19941 points

    Hi Ivan,

    Thank you for your reply and send a friend ship.

    I'll send the data as soon as I get approval with the customer.

    Could you please wait for a while.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Guru* 98255 points

    Hi Shinichi,

    No problem, please share when you can. We'll be waiting for the data.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Guru 19941 points

    Hi Ivan, 

    Thank you for your reply,.

    I could get the approval from the customer.

    I sent with private message.

    Could you please see and advise.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Guru* 98255 points

    Hi Shinichi,

    I'll check on your message and provide further feedback as soon as possible,

    Best regards,
    -Ivan Salazar
    Applications Engineer