VO4157, VO4158
www.vishay.com
Vishay Semiconductors
Rev. 1.8, 14-Feb-12
6
Document Number: 84634
For technical questions, contact: optocoupleranswers@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
Fig. 12 - Basic Power Triac Driver Circuit
POWER FACTOR CONSIDERATIONS
As a zero voltage crossing optotriac, the commutating dV/dt
spikes can inhibit one half of the TRIAC from turning on. If
the spike potential exceeds the inhibit voltage of the
zero-cross detection circuit, half of the TRIAC will be
held-off and not turn-on. This hold-off condition can be
eliminated by using a capacitor or RC snubber placed
directly across the power triac as shown in fig. 11. Note that
the value of the capacitor increases as a function of the load
current.
The hold-off condition also can be eliminated by providing a
higher level of LED drive current. The higher LED drive
provides a larger photocurrent which causes the
phototransistor to turn-on before the commutating spike
has activated the zero-cross detection circuit. For example,
if a device requires 1.5 mA for a resistive load, then 2.7 mA
(1.8 times) may be required to control an inductive load
whose power factor is less than 0.3.
PACKAGE DIMENSIONS in millimeters
21609-1
1
2
3
6
5
4
Control
U1
ZC
R1
360
R
G
330
R
S
C
S
Hot
Nutral
Inductive load
220/240
VAC
i178014
0.20
0.30
3.30
3.81
3.30
3.81
0.84 typ.
7.62 typ.
0.84 typ.
2.54 typ.
1 min.
0.46
0.51
1.22
1.32
6.30
6.50
8.50
8.70
Pin one ID
6
5
4
12
3
18°
3° to 9°
7.62 to 8.81
4° typ.
ISO method A
Option 6
Option 7
20802-41
Option 8
10.16 typ.
7.62 typ.
8 min.
7.62 typ.
4.3 ± 0.3
0.6 min.
10.3 max.
0.7 min.
7.62 typ.
12.1 max.
9.27 min.
3.5 ± 0.3
2.55 ± 0.25
0.1 min.
0.25 ± 0.1
3.5 ± 0.3
2.54
R 0.25
1.78
0.76
1.52
8 min.
11.05
2.54
R 0.25
1.78
0.76
1.52
8 min.
11.05
