PBL 3766
I
I
Ldc
V
TIPX 27/21
-
2.5 V
GND
TR
14/11 RDC
+
V
R
1
TR
L
-
41.7 kΩ
C
DC
V
Bat
RINGX 28/22
Ldc
R
+
DC
V
>V
<V
1
0
TR
SG Ref
Comp
V
TR
SG Ref
-
V
SG Ref
RSG 7/4
0.6
Figure 12. Battery feed (C2, C1 = 1, 0;
active state).
R
SG
V
SG
Saturation Guard
5·105
16/12 RSN
V
I
Ldc
VSGRef = 12.5 +
EE
1000
RSG + 25 kΩ
PBL 3766
3.0·105
VSG = -7.50 –
RSG + 25 kΩ
IL (mA)
RDC = 21.0 kohms
RDC = 41.2 kohms
RDC = 82.5 kohms
40
30
20
10
0
Figure 13. PBL 3766 loop feed examples.
RSG = 0 ohms
500
1000
1500
2000
0
RL
(ohms)
VBat = -58 V to -42 V
13/10
12/9
Ring trip
Comparator
Input
Decoder
C1
C2
I
LTIPX
TIPX
RINGX
V
CC
2-Wire
Interface
27/21
28/22
I
- I
LRINGX
I
LTIPX
LRINGX
2
K
11/8
9/7
DET
E0
+
MUX
62.5 kΩ
Figure 14. Loop current detector.
On-hook to off-hook loop current
-
V
EE
1.25V
22/19 18/13
threshold, ILThOff
:
PBL 3766
RD
VEE
I
LThOff = 8.0 mA for RD → ∞
For ILThOff > 8.0 mA:
R
C
D
D
1
RD =
,
-
5V
ILThOff /KLThOff - 1/62500
KLThOff = 500 V (includes factor K)
4-15
ERICSSON [ ERICSSON ]
