Tripath Technology, Inc. – Preliminary Technical Information
The Soft-Mute function will turn off volume selectively on any of the 6 channels. Setting control bits M1
through MH2 to ‘1’ will issue a Soft-Mute on the corresponding channels. If the VRE bit in the Volume
Change Control Register is set, the volume will first ramp down at a rate defined by the Volume Ramp Rate
Register. Soft-Mute has no affect on whether the differential outputs (Y1 and Y1B through Y4 and Y4B)
continue to switch or not. Clearing bits M1 through MH2 to ‘0’ will re-establish volume on all channels at a
rate defined by the Volume Ramp Enable settings.
The Hard-Mute function is enabled by setting control bit HM high. This function starts with a Soft-Mute on all
channels simultaneously. If the VRE bit in the Volume Change Control Register is set, the volume will first
ramp down at a rate defined by the Volume Ramp Rate Register. Once volume is turned off on all channels,
all differential outputs (Y1 and Y1B through Y4 and Y4B) stop switching. This will reduce power consumption
in the power stages driven by the TCD6001.
When control bit HM is cleared to ‘0’, the Hard-Mute condition is removed, and the TCD6001 goes through
an automatic DC calibration cycle. Once the calibration cycle is complete, volume is re-established on all
channels at a rate defined by the Volume Ramp Enable settings.
The Auto-Mute function is enabled by setting the AM bit to ‘1’. This function detects digital silence (all data
input bits at 0) on all 6 channels lasting more than a pre-defined delay. It then issues a Hard-Mute. The
delay is determined by the contents of the Auto-Mute Timing Register (described below). Upon arrival of
non-zero data on any channel, the Hard-Mute condition is automatically removed. The volume on all 6
channels is re-established at a rate defined by the Volume Ramp Enable settings. The Auto-Mute function
reduces power consumption in the power stages during periods of silence.
Auto-Mute Timing
Addr
2Dh
Register Name
Auto-Mute Timing
Default
D7
AM7
0
D6
AM6
0
D5
AM5
0
D4
AM4
0
D3
AM3
0
D2
AM2
0
D1
AM1
0
D0
AM0
0
This register is only used if the Auto-Mute function is enabled. Its contents specify the duration of silence on
all 6 channels before a Hard-Mute condition is issued. If the number entered is “N”, the duration of silence is
equal to:
(2N + 1) x (1,048,576 periods of LRCK)
As an example, if N = 1 and the period of LRCK is 22.67usec, the period of silence required before a Hard-
Mute condition is issued is:
3 x 1,048,576 x 22.67usec = 71.3 seconds
Volume Change Control
Addr
2Eh
Register Name
Volume Change Control
Default
D7
0
D6
0
D5
0
D4
0
D3
VR1
0
D2
VR0
1
D1
VRE
0
D0
ZCE
0
0
0
0
0
This register is used to specify 3 characteristics of volume change for all channels:
-
-
-
Coarse Gain (control bits VR0 and VR1)
Volume Ramp Enable (control bit VRE)
Zero-Crossing Enable (control bit ZCE)
Coarse Gain is a simple volume adjustment made by shifting bits to the left. Coarse Gain is set by selecting
one of four combinations for bits VR0 and VR1. Coarse Gain affects all 6 channels globally.
Coarse Gain can cause premature digital clipping when used with PGC because internal digital gain
approaches maximum at each PGC boundary. Therefore when using PGC, Coarse Gain should not be
enabled until maximum volume has been reached on all channels.
26
TCD6001 – JL/Rev. 0.9/07.05
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
