B1101CA
| Model | B1101CA |
| Description | SIDACtor devices |
| PDF file | Total 212 pages (File size: 2M) |
| Chip Manufacturer | TECCOR |
Triac Protection
Triac Protection
Thyristors
Damage can occur to a thyristor if the thyristor’s repetitive peak off-state voltage is
exceeded. A thyristor’s repetitive peak off-state voltage may be exceeded due to dirty AC
power mains, inductive spikes, motor latch up, and so on.
Thyristor Reference Circuit
Figure 3.40 and Figure 3.41 show two different methods of protecting a triac. In Figure 3.40,
a
SIDACtor
device is connected from MT2 to the gate of the triac. When the voltage applied
to the triac exceeds the
SIDACtor
device’s V
DRM
, the
SIDACtor
device turns on, producing a
gate current which turns the triac on.
Load
47
Ω
MT2
SIDACtor
To
Gating
Circuitry
Triac
MT1
Hot
Neutral
Figure 3.40
TRIAC Protection
The circuit in Figure 3.41 places a
SIDACtor
device across MT2 and MT1 of the triac. In this
instance the
SIDACtor
device protects the triac by turning on and shunting the transient
before it exceeds the V
DRM
rating of the triac.
Load
Hot
MT2
Triac
To
Gating
Circuitry
MT1
SIDACtor
Neutral
Figure 3.41
TRIAC Protection
With both methods, consider the following designs when using a
SIDACtor
device to protect
a thyristor:
• V
DRM
of the
SIDACtor
device < V
DRM
of Triac
•
SIDACtor
device V
DRM
> 120% V
PK(power supply)
•
SIDACtor
device must be placed behind the load
© 2002 Teccor Electronics
SIDACtor
®
Data Book and Design Guide
3 - 33
http://www.teccor.com
+1 972-580-7777
Reference Designs
