moc3051 Freescale Semiconductor, Inc, moc3051 Datasheet - Page 3

• Manufacturer Part Number: moc3051
• Description: 6-pin Dip Random-phase Optoisolators Triac Drivers
• Manufacturer: Freescale Semiconductor, Inc

Motorola Optoelectronics Device Data
Figure 5. Minimum Time for LED Turn–Off to Zero
1.6
1.4
1.2
0.8
0.6
25
20
15
10
5
0
1
– 40
1
0
Figure 3. Trigger Current versus Temperature
– 30 – 20 –10
Figure 4. LED Current Required to Trigger
2
Cross of AC Trailing Edge
PW in , LED TRIGGER PULSE WIDTH ( s)
T A , AMBIENT TEMPERATURE ( C)
versus LED Pulse Width
0
5
180
10
LED PW
LED TURN OFF MIN 200 s
20
10
30
40
TYPICAL ELECTRICAL CHARACTERISTICS
NORMALIZED TO
20
NORMALIZED TO:
PW in 100 s
T A = 25 C
AC SINE
50
LED CURRENT
60
50
70
80
100
T A = 25 C
I FT versus Temperature (normalized)
the device is expected to operate at an ambient temperature
below 25 C. Multiply the normalized I FT shown on this graph
with the data sheet guaranteed I FT .
Example:
T A = – 40 C, I FT = 10 mA
I FT @ – 40 C = 10 mA x 1.4 = 14 mA
Phase Control Considerations
LED Trigger Current versus PW (normalized)
controllable. They may be triggered at any phase angle with-
in the AC sine wave. Phase control may be accomplished by
an AC line zero cross detector and a variable pulse delay
generator which is synchronized to the zero cross detector.
The same task can be accomplished by a microprocessor
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 s must have an increased ampli-
tude as shown on Figure 4. This graph shows the dependen-
cy of the trigger current I FT versus the pulse width t (PW).
The reason for the I FT dependency on the pulse width can be
seen on the chart delay t(d) versus the LED trigger current.
the minimum specified I FT for static condition, which is speci-
fied in the device characteristic. The normalized I FT has to be
multiplied with the devices guaranteed static trigger current.
Example:
Guaranteed I FT = 10 mA, Trigger pulse width PW = 3 s
I FT (pulsed) = 10 mA x 5 = 50 mA
Minimum LED Off Time in Phase Control Applications
control each AC sine half wave from 0 to 180 degrees. Turn
on at zero degrees means full power and turn on at 180 de-
gree means zero power. This is not quite possible in reality
because 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 driver’s turn on pulse at the trailing edge of
the AC sine wave must be limited to end 200 s before AC
zero cross as shown in Figure 5. This assures that the triac
driver has time to switch off. Shorter times may cause loss of
control at the following half cycle.
This graph shows the increase of the trigger current when
Random Phase Triac drivers are designed to be phase
I FT in the graph I FT versus (PW) is normalized in respect to
In Phase control applications one intends to be able to
MOC3051 MOC3052
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