IL4108-X007(2008) Просмотр технического описания (PDF) - Vishay Semiconductors

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Компоненты Описание

производитель

IL4108-X007
(Rev.:2008)

Optocoupler, Phototriac Output, Zero Crossing, High dV/dt, Low Input Current

Vishay Semiconductors 

IL410/IL4108

Vishay Semiconductors Optocoupler, Phototriac Output, Zero

Crossing,

High dV/dt, Low Input Current

POWER FACTOR CONSIDERATIONS

A snubber isn’t needed to eliminate false operation of the

TRIAC driver because of the IL410/IL4108’s high static and

commutating dV/dt with loads between 1.0 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.

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)*10^0.0066 IL (mA)

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.

0.1

0.01

Ta = 25 °C, PF = 0.3

IF = 2.0 mA

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 2 shows the

0.001

0 50 100 150 200 250 300 350 400

iil410_01 IL - Load Current (mA) (RMS)

Fig. 1 - Shunt Capacitance vs. Load Current

TYPICAL CHARACTERISTICS

Tamb = 25 °C, unless otherwise specified

2.0

IFth Normalized to IFth at PF = 1.0

1.8

Ta = 25 °C

1.6

1.4

1.2

1.0

0.8

0.0 0.2 0.4 0.6 0.8 1.0 1.2

iil410_02

PF - Power Factor

Fig. 2 - Normalized LED Trigger Current vs. Power Factor

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7

0.1

iil410_03

Ta = - 55 °C

Ta = 25 °C

Ta = 85 °C

1

10

100

IF - Forward Current (mA)

Fig. 3 - Forward Voltage vs. Forward Current

www.vishay.com

4

For technical questions, contact: optocoupler.answers@vishay.com

Document Number: 83627

Rev. 1.6, 09-Jan-08

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