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TPA3116D2: 12V power supply

Brian Lancelot
Prodigy 110 points
Part Number: TPA3116D2

Hi, 

Am planning on using the TPA3116D2 to power a pair of 8 ohm speakers rated at 10W RMS each. The power supply is going to be a 12V 2A wall adapter.

Would like to know if the TPA3116D2 is okay to be used with 12V and will there be any harm if I use 2A ?

Thanks in advance.

Regards,

Brian

  • 0
    TI__Guru 61330 points
    Brian,

    Looking at Figure 13. Maximum Output Power (BTL) vs Supply Voltage in the datasheet, 12v is going to be a little short. As you will see with 12V, you need to push past 1% THD to get to 10W at 8Ω.

    Doing basic calculation with 8Ω load, you would need about 13-14v and ~1.25A to hit 10W on one channel.

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 110 points

    Thanks Adam.

    Am planning on using the TPA3116D2 for a pair of Dayton PS95-8 full-range speakers rated at 10W RMS (20W peak). I was looking at putting in not more than 6-8 Watts per channel and was trying to limit the power going into the PS95-8's. So, if the requirement is 6-8 Watts, would a 12V 2A suffice ?

    I'm assuming from the graph 15 on page 10, the 1% THD with 12V is 8W.

    So, 8W x 2 (channels) = 16W, then 16 / 0.85 (approx. 85 percent efficiency) = 18.85W / 12 (volts) = 1.57A (total current required) to drive 8W clean power into each channel or 16W into both channels. Shouldn't 2A be sufficient for this application?

    Please correct me if i am wrong. Is it that I am taking maximum output readings from the graphs when I am looking for 8W RMS rating ?

    Regards,

    Brian

  • 0 in reply to Brian Lancelot
    Guru 140200 points

    Hi Brian,

    should work.

    SPL of "Dayton PS95-8" is 86dB/W/m? Hhm, will not be very load when driving with 6...8W. Each power doubling gives 3dB, so 8W would increase the SPL by 9dB resulting in 95dB/m.

    Kai

  • 0 in reply to Brian Lancelot
    TI__Mastermind 24835 points
    Hi Brian,
    Thanks for your update. Your calculation is correct.
    Best regards,
    Shawn Zheng