Technical Manual
FT420
– Iss 2.4
47
Specifications
Function
60W version
120W version
Voltage input range
20 to 32Vdc
Fuse
5A (blade fuse)
7.5A(blade fuse)
Low voltage shutdown
15V (approx)
Audio input impedance
10kΩ
Output load
4Ω
2Ω
Current draw
– quiescent (standby on)
40mA
Current draw
– quiescent (standby off)
95mA
140mA
Current draw
– full load
14
2.8A
5.3A
Note:
The amplifier standby input is used by Brooks OWS controller to keep quiescent current to a
minimum. If the Brooks OWS standby feature is not used, then the higher current must be used in
quiescent power calculations.
3.9.3 250 Watt Amplifier Module
➢
High energy efficiency class D amplifier design.
➢
Low voltage protection.
➢
Over current protection
➢
Standby function to reduce power consumption.
AU
D I O
OU
T
O
V
E
R
-
CU
RR
E
NT
A UDI O I N
CAL .
S T D B Y
VO LUM E
P O W E R I N ( 2 4 Vd c )
C 1 5
Z 3
Z 2
U 5
R 2 9
R 2 8
R 2 7
R 2 6
R 2 5
R 2 4
R 2 3
R 2 2
R 2 1
R 2 0
R 1 9
Q
2 6
Q
2 5
Q
2 4 Q
2 3
L
E
D
1
D 1 9
D 1 8
C 2 6
C
1
6
C 1 4
D 1 2
R 1 6
C 1 3
R 1 0
R 8
R 3
Q
2 0
Z 1
V R 2
V R 1
U 6
U 4
U 3
U 2
U 1
R 6 0
R 5 9
R 5 8
R 5 7
R 5 6
R 5 5
R 5 4
R 5 3
R 5 1
R 4 9
R 4 8
R 4 5
R 4 3
R 4 2
R 4 1
R 4 0
R 3 8
R 3 7
R 3 4
R 3 3
R 3 2
R 3 1
R 1 5
R 1 3
R 9
R 7
R 6
R 5
R 4
R 2
R 1
Q
1 9
Q
1 8
Q
1 7
Q
1 6
Q
1 5
Q
1 4
Q
1 3
Q
1 2
Q
1 1
Q
9
Q
8
Q
7
Q
6
Q
4
Q
3
Q
2
Q
1
L 2
L 1
F1
D 5
D 4
D 3
D 2
D 1
CO
N3
C O
N 2
C O
N 1
C 3 4
C 3 3
C 3 1
C 3 0
C 2 9
C 2 5
C 2 4
C 2 3
C 2 2
C 2 1
C 2 0
C 1 2
C 1 1
C 1 0
C 9
C 8
C 6
C 5
C 4
C 3
C 2
C 1
C 3 5
C 3 6
C 3 7
R 1 2
D 6
D 7
D 8
D 9
D 1 0
D 1 1
D 1 3
D 1 4
B RO O KS
A US T RA L I A
C 7
D 1 5
D 1 6
D 1 7
Q
5
Q
1 0
Q
2 1
Q
2 2
R 1 1
R 1 4
R 1 7
R 1 8
SUB86 7
PCB21 9 R2
TO SPEA K ER /
1 0 0 V A U D IO TR A N SFO R M ER
VO LU M E A D J U C TM EN T
A U D IO IN PU T
PO W ER IN PU T
STA N D B Y
C A LIB ER A TIO N
( FACTO RY USE O NLY)
FU SE
(1 5 A )
Figure 25 Class-D 250W Audio Amplifier Board Layout
14
Current measured at 27V supply
