Tripath Technology, Inc. – Preliminary Technical Information

33

TCD6000 – Rev. 1.0/09.04

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:

Ω

=

1K

typically

specified,

User

R2

2

2

-

VPP

*

2

R

K

25

R2

*

25K

R3

+

=

R2 = 1k

Ω, 1%

R3 = 13.462k

Ω, 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.

Y

YB

FBN

FBP

R2

R2

R3

R3

TCD6000

V+

LC filter

C

L

V+

LC filter

L

C

Power

Stage