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TCA 785
Phase Control IC TCA 785
Bipolar IC
Features
● Reliable recognition of zero passage
● Large application scope
● May be used as zero point switch
● LSL compatible
● Three-phase operation possible (3 ICs)
● Output current 250 mA
● Large ramp current range
● Wide temperature range
Type Ordering Code Package
P-DIP-16-1
TCA 785 Q67000-A2321 P-DIP-16-1
This phase control IC is intended to control thyristors, triacs, and transistors. The trigger pulses
can be shifted within a phase angle between 0 ˚ and 180 ˚. Typical applications include
converter circuits, AC controllers and three-phase current controllers.
This IC replaces the previous types TCA 780 and TCA 780 D.
Pin Definitions and Functions
Pin Symbol Function
1 GND Ground
2
3
4
5 V
6
7
8 V
Q2
Q U
Q2
SYNC Synchronous voltage
I
Q Z
REF Stabilized voltage
Output 2 inverted
Output U
Output 1 inverted
Inhibit
Output Z
Pin Configuration
(top view)
Semiconductor Group 1
9
10
R
9
C10
Ramp resistance
Ramp capacitance
11 V11 Control voltage
12 C
12 Pulse extension
13 L Long pulse
14
15
16 V
Q 1
Q 2
S Supply voltage
Output 1
Output 2
09.94
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TCA 785
Functional Description
The synchronization signal is obtained via a high-ohmic resistance from the line voltage
(voltage V
synchronization register.
This synchronization register controls a ramp generator, the capacitor C
by a constant current (determined by R
11 (triggering angle ϕ), a signal is processed to the logic. Dependent on the magnitude of the
V
control voltage V
For every half wave, a positive pulse of approx. 30
Q 2. The pulse duration can be prolonged up to 180˚ via a capacitor C
to ground, pulses with a duration between
Outputs and supply the inverse signals of Q 1 and Q 2.
A signal of
A signal whichcorresponds to theNOR linkof Q 1 and Q 2 is available at output Q Z(pin 7).
The inhibit input can be used to disable outputs Q1, Q2 and , .
Pin 13 can be used to extend the outputs and to full pulse length (180˚ –
5). A zero voltage detector evaluates the zero passages and transfers them to the
10 of which is charged
9). If the ramp voltage V10 exceeds the control voltage
11, the triggering angle ϕ can be shifted within a phase angle of 0˚ to 180˚.
µs duration appears at the outputs Q 1 and
12. If pin 12 is connected
ϕ and 180˚ will result.
Q 1 Q 2
ϕ +180˚ which can be used for controlling an external logic,is available at pin 3.
Q 1 Q 2
Q 1 Q 2
ϕ).
Block Diagram
Semiconductor Group 2
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TCA 785
Pulse Diagram
Semiconductor Group 3
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Absolute Maximum Ratings
TCA 785
Inhibit voltage
Control voltage
Voltage short-pulse circuit
Junction temperature
Storage temperature
Thermal resistance
system - air R
Operating Range
Limit Values
min. max.
S – 0.5 18
Q – 10 400
6
V
V11
V13
Q VS
Q VS
Tj
Tstg – 55
th SA 80
– 0.5
– 0.5
– 0.5
V
VS
VS
150
125
UnitParameter Symbol
VSupply voltage V
mAOutput current at pin 14, 15 I
S
V
V
V
µASynchronization input current V5 – 200 ± 200
VOutput voltage at pin 14, 15 V
mAOutput current at pin 2, 3, 4, 7 IQ 10
VOutput voltage at pin 2, 3, 4, 7 V
˚C
˚C
K/W
Characteristics
≤ VS ≤ 18 V; – 25 ˚C ≤ TA ≤ 85 ˚C; f = 50 Hz
8
IS 4.5 16.5 10
S1 … S6 open
11 = 0 V
V
10 = 47 nF; R 9 = 100 kΩ
C
Synchronization pin 5
Input current
2 varied
R
Offset voltage
5 rms
I
∆V5
A – 25 85
Limit Values Test
min. max.
typ.
UnitParameter Symbol
mASupply current consumption
30 1
200
75
µA
mV
VSupply voltage VS 818
HzOperating frequency f 10 500
˚CAmbient temperature T
Circuit
430
Control input pin 11
Control voltage range
Input resistance
V
R11
11
0.2 1
Semiconductor Group 4
V10 peak
V
k
Ω
515
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Characteristics (cont’d)
≤ VS ≤ 18 V; – 25 ˚C ≤ TA ≤ 85 ˚C; f = 50 Hz
8
TCA 785
Ramp generator
Charge current
Max. ramp voltage
Saturation voltage at capacitor
Ramp resistance
Sawtooth return time
Inhibit pin 6
switch-over of pin 7
Outputs disabled
Outputs enabled
Signal transition time
Input current
6 = 8 V
V
Input current
6 = 1.7 V
V
Deviation of I10
R 9 = const.
S = 12 V; C10 = 47 nF
V
Deviation of I
10
R 9 = const.
S = 8 V to 18 V
V
Deviation of the ramp voltage
between 2 following
half-waves, V
S = const.
10
I
V10
V10
R9
tf
V6 L
V6 H
tr
I6 H
– I6L
10
I
I10
∆V10 max
Limit Values Test
min. max.
10
100
3
typ.
225
1000
2 – 2
V
350
300
80
4
1
80
– 5
– 20
3.3
3.3
500
150
± 1
2.5
5
800
200
5
20
UnitParameter Symbol
µA
V
mV
Ω
k
µs
V
V
µs
µA
µA
%
%
%
Circuit
1
1.6
1
1
1
1
1
1
1
1
1
Long pulse switch-over
pin 13
switch-over of S8
Short pulse at output
Long pulse at output
Input current
13 = 8 V
V
Input current
13 = 1.7 V
V
13 H
V
V13 L
I13 H
– I13 L
3.5
45
Outputs pin 2, 3, 4, 7
Reverse current
Q = VS
V
Saturation voltage
Q = 2 mA
I
ICEO
Vsat 0.1
Semiconductor Group 5
2.5
2.5
65
2
10
100
10
2
V
V
µA
µA
µA
V
1
1
1
1
2.6
2.60.4
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Characteristics (cont’d)
≤ VS ≤ 18 V; – 25 ˚C ≤ TA ≤ 85 ˚C; f = 50 Hz
8
TCA 785
Outputs pin 14, 15
H-output voltage
Q = 250 mA
– I
L-output voltage
Q = 2 mA
I
Pulse width (short pulse)
S9 open
Pulse width (short pulse)
with C
12
Internal voltage control
Reference voltage
Parallel connection of
10 ICs possible
TC of reference voltage
V14/15 H
V14/15 L
tp
tp
REF
V
αREF
Limit Values Test
min. max.
VS – 3
0.3
20
530
typ.
V
S – 2.5
0.8
30
620
V
S – 1.0
2
40
760
UnitParameter Symbol
V
V
µs
µs/
nF
2.8 1
3.1
2 × 10
– 4
3.4
5 × 10
– 4
V
1/K
Circuit
3.6
2.6
1
1
1
Semiconductor Group 6
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Application Hints for External Components
min max
Ramp capacitance
Triggering point
C10 500 pF 1 µF
V11 × R9 × C10
2)
tTr =
VREF × K
2)
Charge current
VREF × K
I10 =
R9
Pulse Extension versus Temperature
TCA 785
1)
The minimum and maximum values of I10
are to be observed
Ramp voltage
V10 max = VS – 2 V V10 =
VREF × K × t
R9 × C10
2)
1)
Attention to flyback times
2)
K = 1.10 ± 20 %
Semiconductor Group 7
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Output Voltage measured to + VS
TCA 785
Supply Current versus Supply Voltage
Semiconductor Group 8
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TCA 785
It is necessary for all measurements to adjust the ramp with
the aid of C
e.g. C
10 and R 9 in the way that 3V≤ Vramp max ≤ V S – 2 V
10 = 47 nF; 18 V: R 9 = 47 kΩ; 8 V: R 9 = 120 kΩ
Test Circuit 1
Semiconductor Group 9
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TCA 785
Test Circuit 2
The remaining pins are connected as in test circuit 1
The remaining pins are connected as in test circuit 1
Test Circuit 3
Semiconductor Group 10
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TCA 785
Remaining pins are connected as in test circuit 1
The 10 µF capacitor at pin 5 serves only for test purposes
Test Circuit 4
Test Circuit 5 Test Circuit 6
Semiconductor Group 11
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TCA 785
Inhibit 6 Long Pulse 13
Pulse Extension 12 Reference Voltage 8
Semiconductor Group 12
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TCA 785
Application Examples
Triac Control for up to 50 mA Gate Trigger Current
A phase control with a directly controlled triac is shown in the figure. The triggering angle of
the triac can be adjusted continuously between 0˚ and 180˚ with the aid of an external
potentiometer. During the positive half-wave of the line voltage, the triac receives a positive
gate pulse from the IC output pin 15. During the negative half-wave, it also receives a positive
trigger pulse from pin 14. The trigger pulse width is approx. 100
Semiconductor Group 13
µs.
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TCA 785
Fully Controlled AC Power Controller
Circuit for Two High-Power Thyristors
Shown is the possibility to trigger two antiparalleled thyristors with one IC TCA 785. The trigger
pulse can be shifted continuously within a phase angle between 0˚ and 180˚ by means of a
potentiometer. During the negative line half-wave the trigger pulse of pin 14 is fed to the
relevant thyristor via a trigger pulse transformer. During the positive line half-wave, the gate of
the second thyristor is triggered by a trigger pulse transformer at pin 15.
Semiconductor Group 14
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TCA 785
Half-Controlled Single-Phase Bridge Circuit with Trigger Pulse Transformer and Direct
Control for Low-Power Thyristors
Semiconductor Group 15
Page 16
TCA 785
Half-Controlled Single-Phase Bridge Circuit with Two Trigger Pulse Transformers for
Low-Power Thyristors
Semiconductor Group 16
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