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AIC34_BOOST_SPEAKER_VOLUME.

Mushtaq Syed
Expert 1140 points


Hi:

We are using the AIC34 to drive a 4 ohm speaker connected between HPRCOM and HPLCOM (programmed to be differential). The DACs are programmed for Vcm=1.65V, 0 dB digital volume, 0 dB analog volume and 0 dB output level. At this setting for a full-wave 1Khz sine wave there is no clipping. We tested this on the codec EVM as well as our platform. We are far falling about  3dB SPLC (sound pressure level) short with the above setting. The siganl starts clipping if we increase the level from 0 dB to 1 dB. Are there any tricks to boost the speaker voulme another 3 dBs without causing clipping or other artifacts? Is there a way to use the dynamic range register (#109) to do so?

Thanks a lot!

Cheers,

Mushtaq

  • 0
    TI__Mastermind 28585 points

    Hi Mushtaq,

    The only way you can increase the output range is to increase Avdd. You can use a maximum of 3.6 V on Avdd which will improve the headroom allowing for some more gain to be used at the output stage without clipping. Register 109 will create a small improvement in performance but will not increase the output range.

  • 0 in reply to Converter Apps
    Expert 1140 points

    Sir:

    Thanks a lot!

    Increasing Avdd is an option that I have.

    I am a bit confused about Register 109. I guess I don't understand its usage. I experimented with both dynamic ranges 1 and 2, and the output voltage does increase with these; however, there is clipping. Could you please expound on its usage or refer me to some application note?

    Thanks again!

    Cheers,

    Mushtaq

     

  • 0 in reply to Mushtaq Syed
    TI__Mastermind 28585 points

    Hi,

    Since the AIC family of CODEC is such a low power part, and this low power will tend to limit the noise performance, we added a register that would increase the bias currents in some of the analog sections to bring down the noise. Due to some other circuits in the AIC3106, this feature does not make as big of an impact as we had intended. In some instances, you will see a slight improvement. In others, the improvement is negligible. In either case, it will not impact the headroom, only the noise floor would be impacted.

  • 0 in reply to Converter Apps
    Expert 1140 points

    Sir:

    Thanks you very much!

    Cheers,

    Mushtaq