TISP61089AS POINN [Power Innovations Ltd], TISP61089AS Datasheet - Page 5

• Manufacturer Part Number: TISP61089AS
• Description: DUAL FORWARD-CONDUCTING P-GATE THYRISTORS PROGRAMMABLE OVERVOLTAGE PROTECTORS?
• Manufacturer: POINN [Power Innovations Ltd]

gated protectors
purpose of gated protectors
P R O D U C T
This section covers three topics. Firstly, it is explained why gated protectors are needed. Second, the voltage
limiting action of the protector is described. Third, an example application circuit is described.
Fixed voltage thyristor overvoltage protectors have been used since the early 1980s to protect monolithic
SLICs (Subscriber Line Interface Circuits) against overvoltages on the telephone line caused by lightning, a.c.
power contact and induction. As the SLIC was usually powered from a fixed voltage negative supply rail, the
limiting voltage of the protector could also be a fixed value. The TISP1072F3 is a typical example of a fixed
voltage SLIC protector.
SLICs have become more sophisticated. To minimise power consumption, some designs automatically adjust
the supply voltage, V
supply voltage would be set low, but for long lines, a higher supply voltage would be generated to drive
sufficient line current. The optimum protection for this type of SLIC would be given by a protection voltage
which tracks the SLIC supply voltage. This can be achieved by connecting the protection thyristor gate to the
SLIC supply, Figure 3. This gated (programmable) protection arrangement minimises the voltage stress on
the SLIC, no matter what value of supply voltage.
Figure 2. NON-REPETITIVE PEAK ON-STATE CURRENT AGAINST DURATION
I N F O R M A T I O N
BAT
PEAK NON-REPETITIVE ON-STATE CURRENT
, to a value that is just sufficient to drive the required line current. For short lines the
1.5
0.8
0.7
0.6
0.5
20
15
10
8
7
6
5
4
3
2
1
0.01
APPLICATIONS INFORMATION
CURRENT DURATION
0.1
t — Current Duration — s
DUAL FORWARD-CONDUCTING P-GATE THYRISTORS
THERMAL INFORMATION
RING AND TIP TERMINALS:
I
GROUND TERMINAL:
Current twice I
TSM
1
values applied simultaneously
vs
V
GG
PROGRAMMABLE OVERVOLTAGE PROTECTORS
= -100 V
10
TSM
V
EIA /JESD51
Environment and
PCB, T
GG
value
= -80 V
V
100
A
GG
= 25 °C
= -60 V
TI6LAE
1000
TISP61089AS
OCTOBER 1999
5