TCD6000 Datasheet, PDF (33/36 Pages) Tripath Technology Inc. – 6 CHANNEL CLASS-T DIGITAL AUDIO PROCESSOR USING DIGITAL POWER PROCESSINGTM TECHNOLOGY

Tripath Technology, Inc. – Preliminary Technical Information
V+
Y
LC filter
L
C
TCD6000
Power
Stage ^V+
YB
FBN
FBP
R3
R3
R2
R2
LC filter
L
C
Figure 3 - Feedback network for bridged configurations (1 channel shown)
In bridged configurations like the one shown in Figure 3, R1 is absent (infinity). Since the feedback is now
bridged, the feedback voltage should be cut in half to 2Vpp.
To solve for the values of the feedback resistors in a bridged configuration:
R2 = User specified, typically 1K Ω
R3
=
25K
25 K
*
+
R2
R2
*
VPP
2
-2
For example, in a system with VPP_MAX=30V,
R2 = 1kΩ, 1%
R3 = 13.462kΩ, use 13.3kΩ, 1%
VCLAMP PIN BIASING
The VCLAMP pin must have a DC voltage applied which is proportional to the peak to peak voltage swing of
the power output switching stage in the amplifier system. More explicitly, the potential at VCLAMP should be
0.525 times the peak to peak differential voltage seen at each channel's feedback pins (i.e., the full final
value voltage swing neglecting any RC settling time effects). This means that the component values used in
the circuitry biasing the VCLAMP pin are a direct function of the chosen feedback network components. In a
full bridged system, proper VCLAMP biasing is achieved via a simple two resistor divider between V+ (the
output stage power supply) and ground, shown in the right-hand portion of the circuit below (excluding the
portion in the dotted line box). In a single ended (half bridge) system, VCLAMP biasing is achieved by the
entire six element circuit below.
33
TCD6000 – Rev. 1.0/09.04