U211B2
| Model | U211B2 |
| Description | Phase Control Circuit - General Purpose Feedback |
| PDF file | Total 20 pages (File size: 321K) |
| Chip Manufacturer | TEMIC |
U211B2/ B3
Design Hints
Practical trials are normally needed for the exact
determination of the values of the relevant components in
the load limiting. To make this evaluation easier, the
Parameters
P
max
P
min
P
max
/
min
t
d
t
r
P
max
P
min
t
d
t
r
n.e
R
10
increases
increases
increases
n.e.
n.e.
following table shows the effect of the circuitry on the
important parameters of the load limiting and summarises
the general tendencies.
Component affected
R
9
decreases
decreases
n.e.
decreases
increases
C
9
n.e.
n.e.
n.e.
increases
increases
– maximum continuous power dissipation
– power dissipation with no rotation
– operation delay time
– recovery time
– no effect
P
1
= f
(n)
n 0
P
1
= f
(n)
n = 0
0
Pulse Output Stage
The pulse output stage is short circuit protected and can
typically deliver currents of 125 mA. For the design of
smaller triggering currents, the function I
GT
= f(R
GT
) has
been given in the data sheets in the appendix.
General Hints and Explanation of Terms
To ensure safe and trouble-free operation, the following
points should be taken into consideration when circuits
are being constructed or in the design of printed circuit
boards.
– The connecting lines from C
2
to Pin 7 and Pin 2
should be as short as possible: The connection to Pin 2
should not carry any additional high current such as
the load current. When selecting C
2
, a low
temperature coefficient is desirable.
– The common (earth) connections of the set-point
generator, the tacho-generator and the final
interference suppression capacitor C
4
of the f/V
converter should not carry load current.
– The tacho-generator should be mounted without
influence by strong stray fields from the motor.
– The connections from R
10
and C
5
should be as short
as possible.
To achieve a high noise immunity, a maximum ramp
voltage of 6 V should be used.
The typical resistance R
ö
can be calculated from I
ö
as
follows:
T(ms)
1.13(V)
10
3
R
ö
(k
W
)
C nF)
6(V)
Automatic Retriggering
The variable automatic retriggering prevents half cycles
without current flow, even if the triac is turned off earlier
e.g. due to a collector which is not exactly centered (brush
lifter) or in the event of unsuccessful triggering. If it is
necessary, another triggering pulse is generated after a
time lapse which is determined by the repetition rate set
by resistance between Pin 5 and Pin 3 (R
5-3
). With the
maximum repetition rate (Pin 5 directly connected to
Pin 3), the next attempt to trigger comes after a pause of
4.5 t
p
and this is repeated until either the triac fires or the
half-cycle finishes. If Pin 5 is connected, then only one
trigger pulse per half-cycle is generated. Because the
value of R
5-3
determines the charging current of C
2
, any
repetition rate set using R
5-3
is only valid for a fixed value
of C
2
.
+
T = Period duration for mains frequency
(10 ms at 50 Hz)
C
ö
= Ramp capacitor, max. ramp voltage 6 V
and constant voltage drop at R
ö
= 1.13 V.
A 10% lower value of R
ö
(under worst case conditions)
is recommended.
6 (20)
TELEFUNKEN Semiconductors
Rev. A1, 29-May-96
