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TAS2562: How much could I over-drive a speaker?

Part Number: TAS2562
Other Parts Discussed in Thread: TAS2764, TAS2780, TAS2781, TAS2557, TAS2563,

Hi Team!

From my understanding, TI smart amps are able to pump more power through a speaker than the speaker is rated for. Say I have a 1W speaker, I believe I could pump 2-3W through it without damaging it due to I + V + temp sensing for protection. 

My question is- at what point does it not make sense to overdrive a speaker? (For example, I imagine pumping 6W through a 1W rated speaker would not work or sound weird)

Do we have any resources to help me understand this more? Especially about limitations

Thanks,

Cameron Wutzke

  • Hi Cameron,

    Speaker protection basically tracks the speaker performance in two ways:

    • Excursion limit: Based on the IVsense feedback from the speaker, and a previously obtained electro-mechanical model, the algorithm can predict how much movement a specific frequency/amplitude content will produce on the speaker diaphragm. Then this is compared to a set of Safe Operating Area ranges and if the predicted movement is larger than the maximum excursion set for this particular speaker, some attenuation is applied; otherwise the content is passed through.
    • Thermal limit: Similarly, based on IVsense and the model, the algorithm predicts the voice coil for the content being played, and does a similar attenuation or pass through decision.
    • Here's a detailed document on how the algorithm works: https://www.ti.com/lit/an/slaa857/slaa857.pdf 

    Let me add a few more details you may need to consider:

    • There are two different types of smartamps, integrated and non-integrated. Both have IVsense capabilities, but integrated devices also have embedded processing features to run the speaker protection algorithm in the same IC, along with additional audio processing features like EQ and DRC; examples are TAS2557, TAS2563, TAS2781. The non-integrated devices gather the IVsense data from the speaker, but then rely on the host processor to run the algorithm by sending the IV data through I2S/TDM interface, examples are TAS2562, TAS2764, TAS2780.
    • The speaker electro-mechanical model is obtained during the speaker characterization process. This is usually run using an integrated smartamp EVM, more details available in this document: https://www.ti.com/lit/an/slaa952/slaa952.pdf 

    Hopefully this helps to better understand how the speaker protection works overall. Let us know if there are any further questions.

    Best regards,
    -Ivan Salazar
    Applications Engineer