Q2004D31V
| Model | Q2004D31V |
| Description | Thyristor Product Catalog |
| PDF file | Total 224 pages (File size: 3M) |
| Chip Manufacturer | TECCOR |
AN1009
Application Notes
Examples of Gate Terminations
Primary Purpose
(1) Increase dv/dt capability
(2) Keep gate clamped to ensure V
DRM
capability
(3) Lower t
q
time
Related Effect
— Raises the device latching
and holding current
Primary Purpose
(1) Increase dv/dt capability
(2) Remove high frequency noise
Related Effects
(1)
(2)
(3)
(4)
(5)
Increases delay time
Increases turn-on interval
Lowers gate signal rise time
Lowers di/dt capability
Increases t
q
time
Zener
optional
Primary Purpose
— Decrease threshold
sensitivity
Related Effects
(1) Affects gate signal rise time and di/dt
rating
(2) Isolates the gate
Primary Purpose
— Isolate gate circuit DC
component
Related Effects
— In narrow gate pulses
and low impedance sources, I
gt
followed by
reverse gate signals which may inhibit con-
duction
Curves for Average Current at Various
Conduction Angles
SCR maximum average current curves for various conduction
angles can be established using the factors for maximum aver-
age current at conduction angle of:
30° = 0.40 x Avg 180°
60° = 0.56 x Avg 180°
90° = 0.70 x Avg 180°
120° = 0.84 x Avg 180°
The reason for different ratings is that the average current for
conduction angles less than 180° is derated because of the
higher RMS current connected with high peak currents.
Note that maximum allowable case temperature (T
C
) remains the
same for each conduction angle curve but is established from
average current rating at 180° conduction as given in the data
sheet for any particular device type. The maximum T
C
curve is
then derated down to the maximum junction (T
J
). The curves
illustrated in Figure AN1009.4 are derated to 125 °C since the
maximum T
J
for the non-sensitive SCR series is 125 °C.
125
Primary Purpose
(1) Decrease DC gate sensitivity
(2) Decrease t
q
time
Related Effects
(1) Negative gate current increases holding
current and causes gate area to drop out of
conduction
(2) In pulse gating gate signal tail may
cause device to drop out of conduction
Primary Purpose
— Select frequency
Related Effects
— Unless circuit is
“damped,” positive and negative gate current
may inhibit conduction or bring about spo-
radic anode current
Maximum Allowable Case Temperature (T
C
) –
˚
C
120
115
110
105
Current: Halfwave Sinusoidal
Load: Resistive or Inductive
Conduction Angle: As Given Below
Case Temperature: Measured as
Shown on Dimensional Drawings
Primary Purpose
(1) Supply reverse bias in off period
(2) Protect gate and gate supply for reverse
transients
(3) Lower t
q
time
Related Effects
— Isolates the gate if high
impedance signal source is used without
sustained diode current in the negative cycle
Conduction Angle
100
95
90
85
12
18
30
˚
60
˚
90
˚
0
˚
0
˚
˚
5.1
0
2
4
6
80
7.2
8
10.8 12.8
10
12
14
16
Average On-state Current [I
T
(AV)] – Amps
Figure AN1009.4
Typical Curves for Average On-state Current at
Various Conduction Angles versus T
C
for a
SXX20L SCR
http://www.teccor.com
+1 972-580-7777
AN1009 - 2
©2002 Teccor Electronics
Thyristor Product Catalog
