FAB2200 Datasheet, PDF (19/33 Pages) Fairchild Semiconductor – Audio Subsystem with Stereo Class-G Headphone Amplifier and 1.2W Mono Class-D Speaker Amplifier

Start
Set starting gain
I²C registers
and reset the timers.
yes
Can
no
gain be lowered
by a step while staying
above minimum
gain?
yes
Is the
output amplitude
above the AGC
threshold?
no
Is the
present gain setting
no
below the starting
gain?
yes
no
Has enough
time (attack speed)
passed since the last
gain change?
Has enough
time (decay speed)
no
passed since the last
gain change?
yes
yes
Reduce gain by
1 step and reset
timers.
Figure 22. AGC Flow Chart
Increase gain by
1 step and reset
the timers.
© 2009 Fairchild Semiconductor Corporation
FAB2200 • Rev. 1.0.1
19
www.fairchildsemi.com