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TPA3118D2: power consumption calculate

Jeff YANG
Mastermind 7795 points
Part Number: TPA3118D2

Tool/software:

Hi 

For below TPA3118D2 output waveform, CH1 = OUTP CH2 = OUTN (both left side), when we calculate power consumption, because it sin wave, normarlly we need calculate RMS, mean or maximum?

Now we using CH1(OUTP)-CH2(OUTN) = 6.588V(RMS) 6.588V * CH3(Output current) 583.9mA = 3.84W  3.84W *2 = 7.69W(postive half wave + negative half wave)

7.69W is the RMS power consumption, may I know this understanding is correct? Or we need other calculation to get correct power consumption value?

Thanks!

Jeff

  • 0
    TI__Mastermind 20181 points

    hi Jeff

    what you calculated is output power.

    power consumption is just pvdd * current (the current follow through power supply)

    tks

    jesse

  • 0 in reply to Jesse Ji
    Mastermind 7795 points

    Hi Jesse,

    Q1:

    For below waveform calculate CH1(OUTP)-CH2(OUTN) = 6.588V(RMS) 6.588V * CH3(Output current) 583.9mA = 3.84W,

    We are discuss with customer about not need to using 3.84W*2 since RMS value have already include postive half wave + negative half wave.

    So the power consumption = only 3.84W, is it correct?

    Q2:

    And for below schematic, we want check per channel can output to maximum 10W.

    How to adjust gain divider resistor to make sure the the output power to 10W? (Vin = 16V)

    Q3:

    For TPA3118D2 datasheet show 30-W stereo, 60-W mono, the 30W and 60W means RMS power consumption or peak power consumption?

    Thanks!

    Jeff

  • 0 in reply to Jeff YANG
    TI__Intellectual 1970 points

    Hi Jeff,

    answer to Q1: Yes. but one reminder, if you are using an speaker. usually the power cal can be V*V/R, as this is usually follow speaker vendor. the R is a static value but not real time value.

    answer to Q2: in fact, this depends on your input signal. please make sure the output signal can reach around 13V peak on 8 ohm load. after you get the input signal level and use >13V as output signal level, then you can get your gain setting. then use below table to select the resistors.

    answer to Q3:

    RMS values.

    Br,

    Wenbin