TISP61089SD POINN [Power Innovations Ltd], TISP61089SD Datasheet - Page 6

• Manufacturer Part Number: TISP61089SD
• Description: DUAL FORWARD-CONDUCTING P-GATE THYRISTORS PROGRAMMABLE OVERVOLTAGE PROTECTORS
• Manufacturer: POINN [Power Innovations Ltd]

TISP61089S
DUAL FORWARD-CONDUCTING P-GATE THYRISTORS
PROGRAMMABLE OVERVOLTAGE PROTECTORS
JULY 1999
operation of gated protectors
Figure 4. NEGATIVE OVERVOLTAGE CONDITION
P R O D U C T
6
Figures 4. and 5. show how the TISP61089S limits negative and positive overvoltages. Positive overvoltages
(Figure 5) are clipped by the antiparallel diodes in the TISP61089S and the resulting current is diverted to
ground. Negative overvoltages (Figure 4.) are initially clipped close to the SLIC negative supply rail value
(V
voltage on-state condition. As the overvoltage subsides the high holding current of the crowbar prevents d.c.
latchup. The protection voltage will be the sum of the gate supply (V
(V
capacitor, C1, and the gate terminal. During the initial rise of a fast impulse, the gate current (I
as the cathode current (I
track. To minimise this inductive voltage increase of protection voltage, the length of the capacitor to gate
terminal tracking should be minimised. Inductive voltages in the protector cathode wiring will also increase the
protection voltage. These voltages can be minimised by routing the line to SLIC connection via the protector.
Figure 3. TISP61089S BUFFERED GATE PROTECTOR (SECTION 4.5.12 TESTING CONDITION)
GK(BO)
BAT
). If sufficient current is available from the overvoltage, then the protector (Th5) will crowbar into a low
AI6XBZ
). The protection voltage will be increased if there is a long connection between the gate decoupling
I
K
PROTECTOR
61089S
SLIC
TISP
220 nF
I N F O R M A T I O N
GENERATOR
RESISTANCE
GENERATOR
0 - 600 Vrms
C1
SOURCE
Th5
600
600
A.C.
K
I
G
). Rates of 70 A/µs can cause inductive voltages of 0.7 V in 2.5 cm of printed wiring
WIRE
WIRE
RING
TIP
V
SLIC
BAT
50
50
R1
R2
TISP61089S
220 nF
C1
Th4
Th5
I
G
Figure 5. POSITIVE OVERVOLTAGE CONDITION
I
SLIC
SLIC
I
BAT
AI6XCA
BAT
I
F
V
) and the peak gate-cathode voltage
BAT
PROTECTOR
SWITCHING MODE
POWER SUPPLY
C2
61089S
220 nF
SLIC
TISP
D1
C1
Th5
Tx
AI6XAZ
V
SLIC
BAT
G
) is the same