TPA3128D2: Recommended design Guidelines for custom usage

Jaya krishna

Part Number: TPA3128D2

Hello TI experts,

For one of our new products, we would like to design an amplifier to drive stereo speakers (4 ohm, 8W) using TPA3128. Kindly let me know how this can be done by using TPA3128. Is it done by reducing the VCC of TPA3128 IC? Or is it done by setting PLIMIT pin of the IC? What should be the gain used for this Application? Please let us know the correct design guidelines so that we can proceed with our design.

Thanks

over 2 years ago

0 Yanming Gong over 2 years ago

TI__Mastermind 19010 points

Hi,

TPA3128 is over spec for your application.

I suggest TPA3138 device is more suitable. It can support 10W @ 12V PVDD.

Regards,

Derek

0 Jaya krishna over 2 years ago in reply to Yanming Gong

Prodigy 70 points

Hello Derek,

Thank you for the suggestion.

Can you please share the recommended design for driving 4ohm 7.5W stereo speakers using TPA3138 or TPA3128?

We understand that TPA3138 can support 10W at 12V. We would like to know how it should be designed so that we can drive stereo speakers of 4ohm each at 7.5W(each) making a total of 15W skew. Is this done by reducing VCC or is it done by setting PLIMIT pin of the IC? What should be the recommended gain for this application.

Thanks

0 Yanming Gong over 2 years ago in reply to Jaya krishna

TI__Mastermind 19010 points

Hi,

You can refer EVM design:

https://www.ti.com/lit/ug/slou503/slou503.pdf?ts=1627520934662&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPA3138D2%253FkeyMatch%253DTPA3138

I suggest you reduce PVCC power, since PLIMIT function only limit Vpeak of output, not limit power.

Regards,

Derek

0 Jaya krishna over 2 years ago in reply to Yanming Gong

Prodigy 70 points

Hello Derek,

We tried the following as per your recommendation on TPA3128:

1. Connected the PLIMIT pin to GVD

2. Set PVCC at 7.4V.

We expected the chip to drive 2 speakers of 4 ohm each at nearly 7W (each). But, actually we saw that the amplifier was getting cut off at the highest volume. We saw that the fault was detected when the issue occurred. Kindly let us know the mistake here so that we can correct it.

Thanks

0 Yanming Gong over 2 years ago in reply to Jaya krishna

TI__Mastermind 19010 points

Hi,

Plimit and PVDD limit can not limit power, only limit Vpeak. The power will increase when output clipping.

So the best solution is limit audio input level.

Regards,

Derek

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TPA3128D2: Recommended design Guidelines for custom usage