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Электронный компонент: U208

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U208B
TELEFUNKEN Semiconductors
Rev. A1, 28-May-96
1 (7)
Open Loop Phase Control Circuit
Description
The integrated circuit, U208B, is designed as a phase con-
trol circuit in bipolar technology with internal
supply-voltage monitoring. As the voltage is built up, un-
controlled output pulses are avoided by internal
monitoring. Furthermore, it has internal-current and volt-
age synchronisation. It is recommended as a low cost
open-loop control.
Features
D Automatic retriggering
D Triggering pulse typ. 125 mA
D Voltage and current synchronisation
D Internal supply voltage monitoring
D Current requirement
2.5 mA
Package: DIP8
Block Diagram
236N
95 11224
R
3
220 k
W/
R
4
470 k
W/
V
S
10 nF
GND
C
1
22
mF/
25 V
R
7
180
W
M
R
1
18 k
W/
BYT77
D
1
2 W
TIC
L
N
V
M
=
230 V ~
Supply
voltage
limitation
Output
pulse
Phase
control unit
5
2
1
Voltage
detector
Automatic
retriggering
7
8
3
= f (V
6
)
C
2
100 k
W
Current
detector
Voltage
monitoring
0.5 W
0.5 W
R
2
180 k
W
R
6
18 k
W
R
5
120 k
W
4
6
Figure 1. Block diagram for simple phase control system
U208B
TELEFUNKEN Semiconductors
Rev. A1, 28-May-96
2 (7)
Description
Mains Supply
The U208B is fitted with voltage limiting and can there-
fore be supplied directly from the mains. The supply
voltage between Pin 1 (+ pol/
) and Pin 2 builds up
across D
1
and R
1
and is smoothed by C
1
. The value of the
series resistance can be approximated using figure 1:
R
1
+
V
M
V
S
2 I
S
Further information regarding the design of the mains
supply can be found in the data sheets in the appendix.
Operation using an externally stabilized DC voltage is not
recommended.
If the supply cannot be taken directly from the mains
because the power dissipation in R
1
would be too large,
then the circuit shown in the following figure 2 should be
employed.
1
2
3
4
5
C
1
R
1
24 V~
~
95 10362
Figure 2. Supply voltage for high current requirements
Phase Control
The function of the phase control is largely identical to
that of the well known component TEA1007. The phase
angle of the trigger pulse is derived by comparing the
ramp voltage, which is mains synchronized by the voltage
detector, with the nominal value predetermined at the
control input Pin 6. The slope of the ramp is determined
by C
2
and its charging current. The charging current can
be varied using R
2
on Pin 4. The maximum phase angle
a
max
can also be adjusted using R
2
.
When the potential on Pin 5 reaches the given value of
Pin 6, then a trigger pulse is generated whose width t
p
is
determined by the value of C
2
(the value of C
2
and hence
the pulse width can be evaluated by assuming 8
ms/nF).
The current sensor on Pin 8 ensures that, for operation
with inductive loads, no pulse will be generated in a new
half cycle as long as the current from the previous half
cycle is still flowing in the opposite direction to the sup-
ply voltage at that instant. This makes sure that "Gaps" in
the load current are prevented. The control signal on Pin
6 can be in the range 0 V to 7 V (reference point Pin 1).
If V
pin6
= 7 V then the phase angle is at maximum =
a
max
i.e., the current flow angle is a minimum. The minimum
phase angle
a
min
is when V
pin6
= V
pin1
.
Voltage Monitoring
As the voltage is built up, uncontrolled output pulses are
avoided by internal voltage surveillance. At the same
time, all of the latches in the circuit are reset. Used with
a switching hysteresis of 300 mV, this system guarantees
defined startup behavior each time the supply voltage is
switched on ,or after short interruptions of the mains
supply.
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. In contrast
to the TEA1007, the pulse output stage of the U 208 B has
no gate bypass resistor.
Automatic Retriggering
The automatic retriggering prevents half cycles without
current flow, even if the triacs 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 neces-
sary, another triggering pulse is generated after a time
lapse of t
pp
= 4.5 t
p
and this is repeated until either the
triac fires or the half cycle finishes.
U208B
TELEFUNKEN Semiconductors
Rev. A1, 28-May-96
3 (7)
General Hints and Explanation of Terms
To ensure safe and troublefree operation, the following
points should be taken into consideration when circuits
are being constructed or in the design of printed circuit
boards.
D The connecting lines from C
2
to Pin 5 and Pin 1 should
be as short as possible, and the connection to Pin 1
should not carry any additional high current such as
e.g. the load current.
D When selecting C
2
, a low temperature coefficient is
desirable.
95 10716
V
V
GT
V
L
I
L
p/2
p
3/2
p
2
p
t
p
t
pp
= 4.5 t
p
Mains
Supply
Trigger
Pulse
Load
Voltage
Load
Current
F
Figure 3. Explanation of terms in phase relationship
Absolute Maximum Ratings
Reference point Pin 1, unless otherwise specified
Parameters
Symbol
Value
Unit
Current requirement
Pin 2
I
S
30
mA
q
t
10
ms
i
s
100
Synchronisation current
Pin 8
Pin 7
t < 10
ms
Pin 8
t < 10
ms
Pin 7
I
syncI
I
syncV
"i
I
"i
V
5
5
35
35
mA
Phase control
Input voltage
Pin 6
Input current
Pin 6
Pin 4
V
I
"I
I
I
I
0 to 7
500
1
V
mA
mA
Power dissipation
T
amb
= 45
C
T
amb
= 80
C
P
tot
530
300
mW
Storage temperature range
T
stg
40 to +125
C
Junction temperature
T
j
125
C
Ambient temperature range
T
amb
10 to +100
C
U208B
TELEFUNKEN Semiconductors
Rev. A1, 28-May-96
4 (7)
Thermal Resistance
Parameters
Symbol
Value
Unit
Junction ambient
DlP8
SO8: on p.c. board
SO8: on ceramic
R
thJA
120
220
140
K/W
Electrical Characteristics
V
S
= 13.0 V, T
amb
= 25
C, reference point pin 1, unless otherwise specified
Parameters
Test Conditions / Pins
Symbol
Min.
Typ.
Max.
Unit
Supply voltage for mains
operations
Pin 2
V
S
13.0
V
Limit
V
Supply voltage limitation
I
S
= 3 mA
Pin 2
I
S
= 30 mA
V
S
14.6
14.7
16.6
16.8
V
DC supply current
V
S
= 13 V
Pin 2
I
S
1.0
2.2
2.5
mA
Voltage monitoring
Turn-on threshold
Pin 2
V
SON
11.2
13.0
V
Turn-off threshold
Pin 2
V
SOFF
9.9
10.9
V
Phase control currents
Current synchronisation
Pin 8
I
sync.I
0.35
3.5
mA
Voltage synchronisation
Pin 7
I
sync.V
0.35
3.5
mA
Voltage limitation
"I
I
= 5 mA
Pin 8
Pin 7
"V
I
"V
I
8.0
8.0
8.9
8.9
9.5
9.5
V
Reference ramp
figure 4
Load current
I
S
= f(R
4
)
Pin 5
I
5
1
20
mA
R
-reference voltage
Pin 4, 2
V
Ref
1.06
1.13
1.18
V
Temperature coefficient
Pin 4
TC
V
Ref
0.5
mV/K
Pulse output
Output pulse current
R
7
= 0, V
GT
= 1.2 V
Pin 3
I
o
100
125
150
mA
Reverse current
Pin 3
I
or
0.01
3.0
mA
Output pulse width
C
= 10 nF
Pin 5-1
t
p
80
ms
Automatic retriggering
Repetition rate
Pin 3, 5
t
pp
3
4.5
6
t
p
U208B
TELEFUNKEN Semiconductors
Rev. A1, 28-May-96
5 (7)
0
0.2
0.4
0.6
0.8
0
80
120
160
200
240
Phase
Angle ( )
R
( M
W )
1.0
95 10302
a
10nF
4.7nF
Phase Control
Reference Point Pin 2
2.2nF
C
/t
=1.5nF
Figure 4.
0
3
6
9
12
0
1
2
3
4
6
P
(
W
)
(R1)
I
tot
( mA )
15
95 10317
Mains Supply
5
Figure 5.
Design Calculations for Mains Supply
The following equations can be used for evaluating the
series resistor R
1
for worst case conditions:
R
1max
+ 0.85
V
Mmin
V
Smax
2 I
tot
R
1min
+
V
Mmax
V
Mmin
2 I
Smax
P(
R1max
)
+
(V
Mmax
V
Smin
)
2
2 R
1
where:
V
M
= Mains voltage
V
S
= Supply voltage on Pin 4
I
tot
= Total DC current requirement of the circuit
= I
S
+ I
p
+ I
x
I
S
= Current requirement of the IC in mA
I
p
= Average current requirement of the triggering
pulses
I
x
= Current requirement of other peripheral
components
R
1
can be easily evaluated from figures 6 and 8
0
10
20
30
R
1
( k
W )
40
95 10316
Mains Supply
0
1
2
3
4
6
P
(
W
)
(R1)
5
Figure 6.
0
200
400
600
800
0
20
40
60
80
100
I ( mA
)
GT
R
GT
(
W )
1000
95 10313
Pulse Output
V
GT
= 0.8V
1.4V
Figure 7.
0
4
8
12
0
10
20
30
40
50
R ( k )
1
I
tot
( mA )
16
95 10315
W
Mains Supply
Figure 8.