MOC2R60-10 MOC2R60-15

4

Motorola Optoelectronics Device Data

1.40

0.00

2.00

1.80

1.60

1.20

– 40

TA, AMBIENT TEMPERATURE (°C)

– 20

0

+ 25

+ 40

+ 60

1.00

+ 80

0.60

0.80

0.40

0.20

Figure 9. Holding Current versus

Ambient Temperature

1000

40

TA, AMBIENT TEMPERATURE (°C)

Figure 10. dv/dt versus Ambient Temperature

10

0

– 40

– 20

0

20

80

120

60

100

100

+ 100

Static

Normalized

at 25

°C

Commutating

IT = 30 mA – 2A(RMS)

F = 60 Hz

Phase Control Considerations

LED Trigger Current versus PW (normalized)

The Random Phase POWER OPTO Isolators are designed

to be phase controllable. They may be triggered at any phase

angle within the AC sine wave. Phase control may be accom-

plished by an AC line zero cross detector and a variable pulse

delay generator which is synchronized to the zero cross de-

tector. The same task can be accomplished by a microproces-

sor which is synchronized to the AC zero crossing. The phase

controlled trigger current may be a very short pulse which

saves energy delivered to the input LED. LED trigger pulse

currents shorter than 100

µs must have an increased ampli-

tude as shown on Figure 11. This graph shows the dependen-

cy of the trigger current IFT versus the pulse width t (PW). The

reason for the IFT dependency on the pulse width can be seen

on the chart delay t(d) versus the LED trigger current.

IFT in the graph IFT versus (PW) is normalized in respect to

the minimum specified IFT for static condition, which is speci-

fied in the device characteristic. The normalized IFT has to be

multiplied with the devices guaranteed static trigger current.

Example:

Guaranteed IFT = 10 mA, Trigger pulse width PW = 3 µs

IFT (pulsed) = 10 mA x 5 = 50 mA

Minimum LED Off Time in Phase Control Applications

In phase control applications one intends to be able to con-

trol each AC sine half wave from 0 to 180 degrees. Turn on at

zero degrees means full power, and turn on at 180 degrees

means zero power. This is not quite possible in reality be-

cause triac driver and triac have a fixed turn on time when

activated at zero degrees. At a phase control angle close to

180 degrees the turn on pulse at the trailing edge of the AC

sine wave must be limited to end 200

µs before AC zero

cross as shown in Figure 12. This assures that the device

has time to switch off. Shorter times may cause loss off con-

trol at the following half cycle.

Figure 11. LED Current Required to Trigger

versus LED Pulse Width

PWin, LED TRIGGER PULSE WIDTH (µs)

1

25

20

15

10

5

0

2

5

10

20

50

100

NORMALIZED TO:

PWin ≥ 100 µs

Figure 12. Minimum Time for LED Turn-Off to

Zero Cross of AC Trailing Edge

AC SINE

0

°

180

°

LED PW

LED CURRENT

LED TURN OFF MIN 200

µs