TPA032D02_07 Datasheet, PDF (18/26 Pages) Texas Instruments – 10-W STEREO CLASS-D AUDIO POWER AMPLIFIER

TPA032D02
10ĆW STEREO CLASSĆD AUDIO POWER AMPLIFIER
SLOS243B − DECEMBER 1999 − REVISED JUNE 2000
APPLICATION INFORMATION
class-D effect on power supply (continued)
There is a minor power supply savings with a class-D amplifier versus a linear amplifier when amplifying sine
waves. The difference is much larger when the amplifier is used strictly for music. This is because music has
much lower RMS output power levels, given the same peak output power (see Figure 10); and although linear
devices are relatively efficient at high RMS output levels, they are very inefficient at mid-to-low RMS power
levels. The standard method of comparing the peak power to RMS power for a given signal is crest factor, whose
equation is shown below. The lower RMS power for a set peak power results in a higher crest factor
Crest Factor
+
10 log
P_PK
P_rms
PPK
Time
Figure 10. Audio Signal Showing Peak and RMS Power
PRMS
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