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Audio Amplifier selection

Naveen Kumar S
Intellectual 625 points
Other Parts Discussed in Thread: TLV320AIC3204, TPA2012D2, TPA2026D2, TPA6138A2, TPA6132A2

Hi All,

We are planning to use an audio amplifier for audio application. The current design provides a gain of around 40 dB. We need an additional 15 dB of gain through external amplifier. The audio codec used is TLV320AIC3204. Due to proprietary algorithms in the DSP, we cannot use the complete gain of the audio codec.

HPVDD supply of the audio codec is 3.3V. 

The speaker used is Sonion 2323 ( http://goo.gl/aRYk5k

We would prefer an EVM for our prototype testing. Please suggest.

Please let me know if you need additional inputs.

Thanks & Regards,

Naveen

  • 0
    TI__Guru** 109395 points
    Hi Naveen,

    Could you provide us more details in order to get a better approach?
    What is the output power you need for this application?
    Mono or stereo?
    Is there a specific requirement for Class-AB/Class-D/Headphone?
    What will be the input of the amplifier?

    Best regards,
    -Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Intellectual 625 points

    Hi Ivan,

    Please find the details below:

    We actually need an amplification of 15dB after the audio codec. I am quite not clear on the wattage scale though.

    It is for a stereo application.

    We don't have a requirement for the classes as such. But would prefer the one which is better at noise performance.

    The input to the amplifier will be the output of the audio codec's (TLV320AIC3204) HPL and HPR outputs.

    Thanks,

    Naveen

  • 0 in reply to Naveen Kumar S
    TI__Guru** 109395 points
    Hi Naveen,

    Most of our Class-D and Class-AB amplifiers have selectable or fixed gain.
    Hardware controlled amplifiers have fixed selectable gains. TPA2012D2 is a stereo class-D amplifier with selectable gain of 6, 12, 18 and 24 dB.
    There are software controlled amplifiers like TPA2026D2 that configures gain through I2C from -28 to 30 dB in 1 dB steps, this device also has configurable AGC/DRC.
    There are other amplifiers with boost converter and many of them have battery tracking AGC/ALC and a fixed gain usually of 20 dB.
    D amplifiers are more efficient that AB but they imply a switching signal that may generate noise at high frequencies and require LC filters for better EMI performance.
    These low power D and AB amplifiers usually drive 4 or 8 Ohm loads.

    In the other hand, the headphone amplifiers provide lower output power but drive larger loads like 16 or 32 Ohms that will be very close to the ear. Some of these amplifiers have selectable gain like TPA6132A2 and others have adjustable gain through external resistors like TPA6138A2. These amplifiers are single-ended output and some of them need an output capacitor to remove the DC offset of the output signal that can damage the speakers. Although the DirectPath headphone amplifiers are GND referenced and don't need the output capacitor.

    So, being brief, we may need to know the load you'll drive and at what power you need to drive it. The solution could be a single stereo chip or a two mono chip solution. As you need 15 dB gain I think you may go for the D or AB amplifiers although some of these amplifiers may need to be configured to the closest gain available.

    Best regards,
    -Ivan Salazar
    Texas Instruments