Cirrus Logic CS42L56 - Manual (Page 43)

DS851F2 43
CS42L56
4.5.3 Efficiency
As discussed in previous sections, the amplifiers internal to the CS42L56 operate from one of two sets of
rail voltages, based upon the needs of the signal being amplified or the total gain/attenuation settings. The
power curves for the two modes of operation are shown in
Figure 27 and Figure 28 .
This graph details the power supplied to a load versus the power drawn from the supply for each of the
three use cases.
Output Level
-10 dB
VCP
2
VCP
- VCP
- VCP
2
Amplifier Rail
Voltage
1 second
Time
Time
Figure 26. VHPFILT Hysteresis
Class H Amplifiers automatically
switch between ±VCP and ±VCP/2
to conserve power with typical
headphone loads.
Class AB Amplifiers do not
conserve power with typical
headphone loads.
±VCP/2
±VCP
Figure 27. Class H Power to Load vs. Power from VCP Supply - 32 
All Supplies= 1.8 V
R
L
= 32 