Volume0dBto
+9dB,mute
Volume0dBto
+9dB,mute
VCM
Volume0dBto
+9dB,mute
HPLOUT
HPCOM
HPROUT
DAC_L2
LINE2L
LINE2R
PGA_L
DAC_L1
DAC_R1
VOLUME
CONTROLS,
MIXING
PGA_R
DAC_R2
LINE2L
LINE2R
PGA_L
DAC_L1
DAC_R1
VOLUME
CONTROLS,
MIXING
PGA_R
LINE2L
LINE2R
PGA_L
DAC_L1
DAC_R1
VOLUME
CONTROLS,
MIXING
PGA_R
www.ti.com .............................................................................................................................................. SLOS545C – NOVEMBER 2008 – REVISED MARCH 2009
The output stage architecture leading to the high power output drivers is shown in
Figure 35, with the volume
control and mixing blocks being effectively identical to that shown in
Figure 34. Note that each of these drivers
have a output level control block like those included with the line output drivers, allowing gain adjustment up to
+9dB on the output signal. As in the previous case, this output level adjustment is not intended to be used as a
standard volume control, but instead is included for additional fullscale output signal level control.
Two of the output drivers, HPROUT and HPLOUT, include a direct connection path for the stereo DAC outputs to
be passed directly to the output drivers and bypass the analog volume controls and mixing networks, using the
DAC_L2/R2 path. As in the line output case, this functionality provides the highest quality DAC playback
performance with reduced power dissipation, but can only be utilized if the DAC output does not need to route to
multiple output drivers simultaneously, and if mixing of the DAC output with other analog signals is not needed.
Figure 35. Architecture of the Output Stage Leading to the High Power Output Drivers
The high power output drivers include additional circuitry to avoid artifacts on the audio output during power-on
and power-off transient conditions. The user should first program the type of output configuration being used in
Page-0/Reg-14, to allow the device to select the optimal power-up scheme to avoid output artifacts. The
power-up delay time for the high power output drivers is also programmable over a wide range of time delays,
from instantaneous up to 4-sec, using Page-0/Reg-42.
When these output drivers are powered down, they can be placed into a variety of output conditions based on
register programming. If lowest power operation is desired, then the outputs can be placed into a 3-state
condition, and all power to the output stage is removed. However, this generally results in the output nodes
drifting to rest near the upper or lower analog supply, due to small leakage currents at the pins. This then results
in a longer delay requirement to avoid output artifacts during driver power-on. In order to reduce this required
power-on delay, the TLV320AIC3107 includes an option for the output pins of the drivers to be weakly driven to
the VCM level they would normally rest at when powered with no signal applied. This output VCM level is
determined by an internal bandgap voltage reference, and thus results in extra power dissipation when the
drivers are in powerdown. However, this option provides the fastest method for transitioning the drivers from
powerdown to full power operation without any output artifact introduced.
Copyright 2008–2009, Texas Instruments Incorporated
43