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TPA2012D2 increase gain > 24dB?

Theng Hoo Koay
Prodigy 160 points
Other Parts Discussed in Thread: TPA2012D2

Hi there,

In this project we are using 4 Ohm 2W speakers as output, and input comes from MP3 player, handphone, etc. VCC = 5VDC. All components that we assemble to our PCB are exactly the same as EVA board, except the TPA2012D2 is QFN type.

Our issue now is when we play the music, at certain level of volume, we still can get good sound, but when the input volume increased the sound getting bad. And at maximum volume, one side or even both side of the output will shutdown. And it will steady OFF until we remove or switch OFF the power supply and ON it again.

For example, when we use galaxy note 2 as input, we still can get good sound at level 12 of volume. At level 13, the sound very bad and at level 14, it will shut down. We can't even go to level 15. This issue also found at demo board that we receive.

Is there any others way how to setup (increase) the output gain to >24dB instead of by connecting G0/G1 to GND? With 18dB gain or 24dB, the sound is not loud enough for our application.

Please advise

Cheers.

  • 0
    TI__Guru**** 189401 points

    Hi, Kaoy,

    I apologize, we missed your post.

    Did you get this sorted out by now?

    It sounds to me like you have a problem with your load resistance (maybe the speaker is much lower than 4R at some frequency), output filter, decoupling capacitance, or PCB layout. From the symptoms you describe, you are tripping the short-circuit protection, and these four items are the most common causes for this.

    -d2

  • 0 in reply to Don Dapkus
    Prodigy 160 points

    Hello Don,

    Thanks for your reply. Will try out some approaches suggested by you to see whether it is able to solve this problem.

    Will update you again once we done it.

    Cheers.

    - Koay

  • 0 in reply to Theng Hoo Koay
    Prodigy 160 points

    Hello Don,

    Good day.

    After some testing and validation, the main issues are coming from thermal. We put heatsink on the chipset and noise problems are solved.

    But, heatsink is not able to apply during mass production as limitation on the PCB space. Could you help to review on the schematic/gerber files and suggest the improvement on the PCB layout to well handle the heat dissipation?

    0243.TPA2012 PCB Gerber.zip

    5707.Music Plug Main.pdf

    Thanks a lot.

    -Koay

  • 0 in reply to Theng Hoo Koay
    Prodigy 160 points

    Hello Don,

    Any suggestion on my previous post?

    Thanks for your prompt attention.

    -Koay.

  • 0 in reply to Theng Hoo Koay
    TI__Guru**** 189401 points

    Hi, Koay,

    Oops, sorry I missed your follow-up post.

    It seems that your PCB is VERY small, and I doubt it has space to dissipate the heat generated for 2W/4Rx2 speakers. I also noticed that your footprint doesn't follow the recommended thermal landing pattern in the data sheet.

    Some ways to improve thermal performance:

    1. Use heaver weight copper. We use 1 oz on our EVMs, but 2 oz is much better thermally.

    2. Add more vias under the PowerPAD(tm). It looks like you have four, our recommended thermal landing pattern shows nine.

    3. Add more layers to your PCB - you have two layers, increasing it to four layers (with the internal two just being ground planes, tied to the vias under the PowerPAD).

    4. Re-route the back of the board - the copper area is quite broken up by the traces you routed there. In fact, if you change to 4-layer, move those traces to an internal layer, and make the back solid ground plane.

    5. Increase the board size.

    6. Use a higher resistance load to decrease the power dissipation (of course, your output level may be reduced, depending on the sensitivities of the speakers that you're using).

    -d2

  • 0 in reply to Don Dapkus
    Prodigy 160 points

    Hello Don,


    Thank you so much on your suggestions.

    We will look into in again.

    -Koay.