IL4217 Просмотр технического описания (PDF) - Vishay Siliconix
Номер в каталоге
Компоненты Описание
производитель
IL4217 Datasheet PDF : 8 Pages
| |||
IL4216/IL4217/IL4218
Vishay Semiconductors Optocoupler, Phototriac Output,
High dV/dt, Very Low Input Current
POWER FACTOR CONSIDERATIONS
A snubber is not needed to eliminate false operation of the
TRIAC driver because of the IL4216/IL4217/IL4218 high
static and commutating dV/dt with loads between 1 and 0.8
power factors. When inductive loads with power factors less
than 0.8 are being driven, include a RC snubber or a single
capacitor directly across the device to damp the peak
commutating dV/dt spike. Normally a commutating dV/dt
causes a turning-off device to stay on due to the stored
energy remaining in the turning-off device.
But in the case of 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 snubber or capacitor placed directly
across the optotriac as shown in Figure 1. 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 network. Figure 8 shows the
relationship of the LED drive for power factors of less than
1.0. The curve shows that if a device requires 1.5 mA for a
resistive load, then 1.8 times (2.7 mA) that amount would be
required to control an inductive load whose power factor is
less than 0.3.
1
CS (µF) = 0.0032 (µF) x 10 ^ (0.0066 IL(mA))
0.1
0.01
0.001
0
iil4116_07
PF = 0.3
IF = 2.0 mA
50 100 150 200 250 300 350 400
IL - Load Current (mA)
Fig. 3 - Shunt Capacitance vs. Load Current vs. Power Factor
2.0
1.8
1.6
1.4
1.2
IFth Normalized to I Fth at PF = 1.0
1.0
0.8
0
0.2 0.4 0.6 0.8 1.0 1.2
iil4116_08
PF - Power Factor
TYPICAL CHARACTERISTICS
Tamb = 25 °C, unless otherwise specified
35
30
25
20
15
10
5
0
1.0
1.1
1.2
1.3
1.4
iil4116_01
VF - LED Forward Voltage (V)
Fig. 4 - Normalized LED Trigger Current
1.4
1.3
TA = - 55 °C
1.2
1.1
TA = 25 °C
1.0
0.9
TA = 100 °C
0.8
0.7
0.1
1
10
100
iil4116_02
IF - Forward Current (mA)
Fig. 5 - LED Forward Current vs. Forward Voltage
Fig. 6 - Forward Voltage vs. Forward Current
www.vishay.com
4
For technical questions, contact: optocoupler.answers@vishay.com
Document Number: 83630
Rev. 1.4, 09-Jan-08
Share Link: 