User Manual

The TPA005D02 Audio Power Amplifier Evaluation Module
3-21
Details
3.2.4.4 Class D Effect on Battery Life
Battery operations for class D amplifiers versus linear amplifiers have similar
power supply savings. The essential contributing factor to longer battery life
is lower RMS supply current. Figure 3–17 compares the TPA005D02 supply
current to the supply current of the TPA0202, a 2-W linear device, while playing
music at different peak voltage levels.
Figure 3–17. Supply Current vs Peak Output Voltage of TPA005D02 vs TPA0202 with
Music Input
400
350
250
200
150
0
300
1 1.5 2 2.5
Supply Current (mA rms)
SUPPLY CURRENTS
vs
PEAK OUTPUT VOLTAGE AND PEAK OUTPUT POWER
43
3.5
100
50
0.25 0.56 1 1.56 42.25
3.06
Peak Output Voltage (V)
Peak Output Power (W)
TPA0202
TPA005D02
This plot shows that a linear amplifier has approximately three times more
current draw at normal listening levels than a class D amplifier. Thus, a class
D amplifier has approximately three times longer battery life at normal listening
levels. If there is other circuitry in the system drawing supply current, that must
also be taken into account when estimating battery life savings.