CLP200M_03 Datasheet, PDF (4/21 Pages) STMicroelectronics – OVERVOLTAGE AND OVERCURRENT PROTECTION FOR TELECOM LINE

CLP200M
APPLICATION CIRCUIT : CLP200M in line card
Fig. 3 : CLP200M in line card
I
Fuse
TIP
R sense
TIPL
TIPS
1
-Vbat
Overcurrent
detector
OR
SW3 SW1
Overvoltage
detector
Overvoltage
reference
(+/- 215 V)
Rp
2
External
voltage
reference
-Vbat
(*)
TIP
SLIC
FS
SW4 SW2
OR
Overvoltage
detector
Overvoltage
reference
(+/- 215 V)
GND
1
Rp
RING
2
Overcurrent
ct(s) ^RING
Fuse
detector
RINGL
R sense
RINGS
Ring
Generator
rodu ^{(*) LCP1511D or THDT series}
P _{Figure 3 above shows the topology of a protected}
te _{analog subscriber line at the exchange side. The}
le ^{CLP200M is connected to the ring relay via two}
o balanced Rp resistors, and to the Subscriber Line
s _{Interface Circuit. A second device is located near}
b _{the SLIC : it can be either a LCP1511D or a THDT}
O series.
- _{These two devices are complementary and their}
) _{functions are explained below :}
t(s ^{s The first stage based on CLP200M manages}
c the high power issued from the external
u surges. When used in ringing mode, the
d _{CLP200M operates in voltage mode and pro-}
ro ^{vides a symmetrical and bidirectional}
overvoltage protection at +/-215 V on both TIP
P _{and RING lines. When used in speech mode,}
te ^{the CLP200M operates in current mode and}
le ^{the activation current of the CLP200M is ad-}
Obso ^{justed by RSENSE.}
s The second stage is the external voltage refer-
ence device which defines the firing threshold
voltage during the speech mode and also as-
sumes a residual power overvoltage
suppression. This protection stage can be either
a fixed or programmable breakover device. The
THDTxx family acts as a fixed breakover device
while the LCP1511D operates as a programma-
ble protection.
Thanks to this topology, the surge current in the
line is reduced after the CLP200M. Because the
remaining surge energy is low, the power ratings of
Rp, the ring relay contacts and the external voltage
reference circuit may be downsized. This results in
a significant cost reduction.
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