Low power audio amp

Discussion in 'The Projects Forum' started by tinusw7, Dec 21, 2011.

  1. tinusw7

    Thread Starter New Member

    Dec 21, 2011
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    0
    Hi
    I have built an audio player based on the ATTiny85 and will run it with battery power. As the microcontroller does not deliver enough power for the speaker, I need an amplifier for the audio signal. When the player is not playing a song, it should consume almost no energy in order to have a long battery life. The microcontroller in sleep mode is no problem, but the amplifier quiet power consumption should be near 0 mA as well. The audio amplifier chips that I´ve found so far () have a quiet current of 4mA which is too high. Do you know a good low power audio amplifier solution? Thanks a lot for all advice.


    Regards
    Martin
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. jimkeith

    Active Member

    Oct 26, 2011
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  4. crutschow

    Expert

    Mar 14, 2008
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    With the Maxim class D amp bertus suggested you just need to disable it when the μC is in the sleep mode. When disabled the amp only draws a few microamps.
     
  5. tinusw7

    Thread Starter New Member

    Dec 21, 2011
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    Thank you all for the info, will look closer to the Maxim chips (both of them).

    /Martin
     
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Here is a TPA3125D2N from DigiKey

    $2.64 + cheap support components,Typical Circuit on page 1 of the datasheet

    0.39mA quiescent current in shutdown/sleep mode

    TypeClass D
    Output Type1-Channel (Mono) or 2-Channel (Stereo)
    Max Output Power x Channels @ Load36W x 1 @ 8 Ohm; 10W x 2 @ 8 Ohm
    Voltage - Supply10 V ~ 26 V
    FeaturesDepop, Mute, Short-Circuit and Thermal Protection, Shutdown
    Mounting TypeThrough Hole
    Supplier Device Package20-PDIP
     
  7. tinusw7

    Thread Starter New Member

    Dec 21, 2011
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    Thank you for the suggestion, looked good but then I realized that I forgot to say that the supply voltage is 3V, i.e. wont work with that one. Sorry for that but thanks anyway!

     
  8. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Please specify voltage when asking. :)

    No Through hole, but large surface mount is available

    TDA749313

    TypeClass D
    Output Type2-Channel
    Max Output Power x Channels @ Load3W x 2 @ 4 Ohm
    Voltage - Supply3 V ~ 5.5 V
    FeaturesDifferential Inputs, Short-Circuit and Thermal Protection, Shutdown
    Mounting TypeSurface Mount
    Supplier Device Package24-HTSSOP
     
    tinusw7 likes this.
  9. tinusw7

    Thread Starter New Member

    Dec 21, 2011
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    Yes, will remember that for the future :)

    Thank you, this one looks really good, only 1uA standby current! I'll order this one and do some tests.

    /Martin


     
  10. skycarl

    New Member

    Nov 16, 2011
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    That really is a nice amplifier. Kind of wants to make you put a circuit together just to
    use it.
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    The TDA7493 IC is rated only when its supply is 5V then its output power is 2.2W into 4 ohms at 1% distortion. It might barely have any output with a 3V supply and might have no output when the battery drops below 3V.
     
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