U2010B-M 데이터 시트보기 (PDF) - Atmel Corporation
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U2010B-M Datasheet PDF : 13 Pages
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U2010B
necessary with a high repetition rate, tpp/tp, until the triac
remains reliably triggered.
Current Synchronization
Current synchronization fulfils two functions:
* Monitoring the current flow after triggering.
In case the triac extinguishes again or it does not switch
on, automatic triggering is activated until the
triggering is successful.
* Avoiding a triggering due to inductive load.
In the case of inductive load operation, the current
synchronization ensures that in the new half wave no
pulse is enabled as long as there is a current available
from the previous half wave, which flows from the
opposite polarity to the actual supply voltage.
A special feature of the integrated circuit is the
realization of this current synchronization. The device
evaluates the voltage at the pulse output between gate and
reference electrode of the triac. This results in saving
separate current synchronization input with specified
series resistance.
Voltage Synchronization with Mains Voltage
Compensation
The voltage detector synchronizes the reference ramp
with the mains supply voltage. At the same time, the
mains-dependent input current at Pin 15 is shaped and
rectified internally. This current activates the automatic
retriggering and at the same time is available at Pin 5. By
suitable dimensioning, it is possible to obtain the speci-
fied compensation effect. Automatic retriggering and
mains voltage compensation are not activated until
|V15 – 10| increases to 8 V. The resistance Rsync. defines
the width of the zero voltage cross over pulse, synchroni-
zation current, and hence the mains supply voltage
compensation current.
If the mains voltage compensation and the automatic
retriggering are not required, both functions can be
suppressed by limiting |V15 – 10| v 7 V, see figure 4.
Load-Current Compensation
The circuit continuously measures the load current as a
voltage drop at resistance R6. The evaluation and use of
both half waves results in a quick reaction to load-current
change. Due to voltage at resistance R6, there is a
difference between both input currents at Pins 1 and 2.
This difference controls the internal current source,
whose positive current values are available at Pins 5
and 6. The output current generated at Pin 5 contains the
difference from the load-current detection and from the
mains voltage compensation, see figure 2.
The effective control voltage at Pin 4 is the final current
at Pin 5 together with the desired value network. An
increase of mains voltage causes the increase of control
angle α, an increase of load current results in a decrease
in the control angle. This avoids a decrease in revolution
by increasing the load as well as an increase of revolution
by the increment of mains supply voltage.
Load-Current Limitation
The total output load current is available at Pin 6. It
results in a voltage drop across R11. When the potential
of the load current reaches about 70% of the threshold
value (VT70), i.e., about 4.35 V at Pin 6, it switches the
high-load comparator and opens the switch between
Pins 11 and 12. By using an LED between these pins
(11 and 12), a high-load indication can be realized.
If the potential at Pin 6 increases to about 6.2 V (= VT100),
it switches the overload comparator. The result is
programmable at Pin 9 (operation mode).
Mains
R2
2x
BZX55
C6V2
15
U2010B
10
Figure 4. Suppression of mains voltage compensation
and retrigger automatic
Mode selection:
a) αmax (V9 = 0)
In this mode of operation, Pin 13 switches to –VS
(Pin 11) and Pin 6 to GND (Pin 10) after V6 has
reached the threshold VT100. A soft-start capacitor is
then shorted and the control angle is switched to
αmax. This position is maintained until the supply
voltage is switched off. The motor can be started
again with soft-start function when the power is
switched on again. As the overload condition
switches Pin 13 to Pin 11, it is possible to use a
smaller control angle, αmax, by connecting a further
resistance between Pins 13 and 14.
4 (13)
Rev. A4, 23-Nov-00
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