max98088 Maxim Integrated Products, Inc., max98088 Datasheet - Page 98

• Manufacturer Part Number: max98088
• Description: Stereo Audio Codec With Flexsound Technology
• Manufacturer: Maxim Integrated Products, Inc.

Speaker Output Volume
Table 23. Speaker Output Mixer Register
Stereo Audio Codec
with FLEXSOUND Technology
The IC includes signal processing to improve the sound
quality of the speaker output and protect transducers
from damage. An excursion limiter dynamically adjusts
the highpass corner frequency, while a power limiter and
distortion limiter prevent the amplifier from outputting too
much distortion or power. The excursion limiter is located
in the DSP while the distortion limiter and power limiter
control the analog volume control (Figure 28). All three
limiters analyze the speaker amplifier’s output signal to
determine when to take action.
The excursion limiter is a dynamic highpass filter that
monitors the speaker outputs and increases the high-
pass corner frequency when the speaker amplifier’s out-
put exceeds a predefined threshold. The filter smoothly
98
REGISTER
0x3D/0x3E
Speaker Amplifier Signal Processing
BIT
7
4
3
2
1
SPVOLL/SPVOLR
SPLM/SPRM
NAME
Excursion Limiter
Left/Right Speaker Output Mute
0 = Disabled
1 = Enabled
Left/Right Speaker Output Volume Level
VALUE
0x0C
0x0D
0x0A
0x0B
0x0E
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0F
transitions between the high and low corner frequency to
prevent unwanted artifacts. The filter can operate in four
different modes:
U Fixed-Frequency Preset Mode. The highpass corner
U Fixed-Frequency Programmable Mode. The high-
U Preset Dynamic Mode. The highpass filter automati-
U User-Programmable Dynamic Mode. The highpass
VOLUME (dB)
frequency is fixed at the upper corner frequency and
does not change with signal level.
pass corner frequency is fixed to that specified by the
programmable biquad filter.
cally slides between a preset upper and lower corner
frequency based on output signal level.
filter slides between a user-programmed biquad filter
on the low side to a predefined corner frequency on
the high side.
-62
-58
-54
-50
-46
-42
-38
-35
-32
-29
-26
-23
-20
-17
-14
-12
DESCRIPTION
VALUE
0x1C
0x1D
0x1A
0x1B
0x1E
0x10
0x11
0x12
0x13
0x14
0x15
0x16
0x17
0x18
0x19
0x1F
VOLUME (dB)
+6.5
+7.5
-10
+1
+2
+3
+4
+5
+6
+7
+8
-8
-6
-4
-2
0