CLP200M_03 Datasheet, PDF (6/21 Pages) STMicroelectronics – OVERVOLTAGE AND OVERCURRENT PROTECTION FOR TELECOM LINE

CLP200M
s external reference supplies, V_b1 and V_b2 (see fig.5b)..
Fig. 5b : Method to adjust the reference voltage.
Fuse
TIP
R sense
TIPL
TIPS
1
Rp
2
Overcurrent
detector
VB1
OR
Overvoltage
detector
Overvoltage
reference
SW3 SW1
(+/- 215 V)
FS
GND
SW4 SW2
OR
Overvoltage
detector
Overvoltage
reference
(+/- 215 V)
roduct(s) ^RING
Fuse
Overcurrent
detector
RINGL
R sense
RINGS
lete ^P _{2.4 Speech mode}
so _{Fig. 6 : Switching by current during speech mode.}
b _ILG
Fuse
O _TIP
R sense
) ^{- TIPL}
TIPS
1
t(s Overcurrent
c ^detector
Rp
2
du OR
ro ^{SW3 SW1}
Overvoltage
detector
Overvoltage
reference
VLG
(+/- 215 V)
FS
GND
-Vbat
External
voltage
reference
VB2
1
Rp
2
ILG
A2
4
-VREF2
5
VREF1
6
VLG
olete ^P _{In speech mode (Ring relay in position 1), the pro-}
s _{tection is provided by the combination of both}
b_{CLP200M and the external voltage reference de-}
O_vice.
The operating point moves to region 5 for positive
surges or region 6 for negative surges.
Once the surge current falls below the switch-
ing-off current I_SWOFF, the CLP200M returns to its
In normal conditions, the working point of this cir- ^{initial state (region 4).}
cuit is located in region 4 of A2 curve : the
CLP200M is idle.
When a surge occurs on the line, the external volt-
age reference device clamps at GND or -V_bat re-
spectively for positive and negative surges.
This generates a current which is detected by
R_SENSE and causes the protection to act : the line is
Furthermore, the CLP200M switches when an
overvoltage, either positive or negative, occurs ei-
ther :
s simultaneously on both TIP and RING lines ver-
sus GND.
s between TIP and RING.
short-circuited to GND.
s on TIP (or RING) versus GND.
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