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Can the TPA3140D2 be used with 45 ohm speakers.What kind of power levels can I expect with 5 volt supply.

JERRY COHEN
Prodigy 100 points

What kind of performance can I expect at 100 mw to 3 watts into a 45 ohm speaker. By the way we manufacture our own loudspeakers for industrial and Military needs. By combining switching step down power supply and class D amplifier. I can operate from 6-36vdc. 

  • 0
    Prodigy 60 points
    The data sheet indicates that PVCC is the maximum output voltage the device can give. Based on setting this to 5V the output will also be limited to 5V. This calculates to an RMS power of 0.25W. If you need more power you will require a lower impedance loudspeaker or a larger supply voltage.
    Regards
    Paul
  • 0 in reply to Wilson Paul24
    TI__Mastermind 34305 points

    Hi Jerry,

    I would to expand on Paul's reply.  The calculation for the voltage needed to drive a specified load to a certain power is simple.  We need to calculate the peak voltage needed to across the 45 ohm speaker.  

    V*V/R = P,  We know the P and the R, so V is easy to calculate.

    V will be your RMS power, so it needs to be converted to peak.  

    Vrms*1.414= Vpeak,  

    Let's plug in some numbers.  P = 3W, and R = 45 ohms

    V=11.62Vrms  And Vp = 16.43Vp

    With a full bridge amplifier, the power supply voltage needed is 16.43Vdc plus some some more for system losses.  A variable power supply on our EVM will help you here.