Cirrus Logic CS43L22 - Manual (Page 27)

DS792F2 27
CS43L22
Confidential Draft
3/4/10
4.5.1 Mono Speaker Output Configuration
The CS43L22 accommodates a stereo as well as a mono speaker output configuration. In mono mode
the output drivers of each channel are connected in parallel to deliver maximum power to a 4 ohm speak-
er. Refer to the table below for pin mapping in mono configuration.
4.5.2 VP Battery Compensation
The CS43L22 provides the option to maintain a desired power output level, independent of the VP supply.
When enabled, this feature works by monitoring the voltage on the VP supply and reducing the attenua-
tion on the speaker outputs when VP voltage levels fall.
Note: The internal ADC that monitors the VP supply operates from the VA supply. Calculations are based
on typical VA levels of 1.8 V and 2.5 V using the VPREF bits.
4.5.2.1 Maintaining a Desired Output Level
Using SPKxVOL, the speaker output level must first be attenuated by the decibel equivalent of the expect-
ed VP supply range (MAX relative to MIN). The CS43L22 then gradually reduces the attenuation as the
VP supply drops from its maximum level, maintaining a nearly constant power output.
Compensation Example 1 (VP Battery supply ranges from 4.5 V to 3.0 V)
1. Set speaker attenuation (SPKxVOL) to -3.5 dB. The VP supply changes ~3.5 dB.
2. Set the reference VP supply (VPREF) to 4.5 V.
3. Enable battery compensation (BATTCMP).
The CS43L22 automatically adjusts the output level as the battery discharges.
Compensation Example 2 (VP Battery supply ranges from 5.0 V to 1.6 V)
1. Set speaker attenuation (SPKxVOL) to -10 dB. The VP supply changes ~9.9 dB.
2. Set the reference VP supply (VPREF) to 5.0 V.
3. Enable battery compensation (BATTCMP).
The CS43L22 automatically adjusts the output level as the battery discharges. Refer to Figure 11 on
page 28 . In this example, the VP supply changes over a wide range, illustrating the accuracy of the
CS43L22’s battery compensation.
Pin
Speaker Output
SPKMONO=0 SPKMONO=1
SPKSWAP=0 SPKSWAP=1 SPKSWAP=0 SPKSWAP=1
4 SPKOUTA+ SPKOUTB+ SPKOUTA+ SPKOUTB+
6 SPKOUTA- SPKOUTB- SPKOUTA+ SPKOUTB+
7 SPKOUTB+ SPKOUTA+ SPKOUTA- SPKOUTB-
9 SPKOUTB- SPKOUTA- SPKOUTA- SPKOUTB-
Referenced Control Register Location
SPKMONO..........................
SPKSWAP........................... “Speaker MONO Control” on page 46
“Speaker Channel Swap” on page 45