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Page 24 of 50
IRAUDAMP5 REV 3.1
Bridged Output
The IRAUDAMP5 is not intended for a bridge-tied-load, or BTL configuration. However, BTL
operation can be achieved by feeding out-of-phase audio input signals to the two input channels
as shown in the figure 27 below. In BTL operation, minimum load impedance is 8 Ohms and
rated power is 240W non-clipping. The installed clamping diodes D5 – D8 are required for BTL
operation, since reactive energy flowing from one output to the other during clipping can force
the output voltage beyond the voltage supply rails if not clamped.
+
-
.
.
+
-
INPUT
R14
10k 1%
IN-
COMP
C24
.
R34
COMP
C23
C1
R21
R33
.
C17
+VAA
IRS2092S
IRS2092S
LO
VS
VCC
VB
HO
LO
VS
VCC
VB
HO
-B
+B
-B
+B
L2
0V
L1
0V
-B
.
-B
+B
R13
C2
C18
IN-
+VAA
LP Filter
LP Filter
+B
CH2
C22
1
R32
CH1
C21
R31
COM
Integrator
Modulator
and
Shift level
GND
COM
Integrator
Modulator
and
Shift level
GND
D6
D8
D7
10
k 1%
D5
IRF6645
Q6
IRF6645
Q3
IRF6645
Q5
IRF6645
Q4
Bridged configuration
Fig 27
Output Filter Design, Preamplifier and Performance
The audio performance of IRAUDAMP5 depends on a number of different factors. The section
entitled, “Typical Performance” presents performance measurements based on the overall system,
including the preamp and output filter. While the preamp and output filter are not part of the
Class D power stage, they have a significant effect on the overall performance.
Output filter
Since the output filter is not included in the control loop of the IRAUDAMP5, the reference
design cannot compensate for performance deterioration due to the output filter. Therefore, it is
important to understand what characteristics are preferable when designing the output filter:
Summary of Contents for IRAUDAMP5
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