U2044B
Dual Output Flasher
Description
The integrated circuit U2044B is used in relay controlled
automotive flashers. With two output stages each side of
the vehicle is controlled separately. A left and a right
direction indicator input with only a small control current
makes switch contacts for small loads possible.
The separate hazard warning input simplifies the
construction of the hazard switch. Lamp outage is indi-
cated by frequency doubling during direction mode.
Thanks to the extreme low current consumption U2044B
can be connected to the battery directly.
Features
D
Temperature and supply voltage compensated
flashing frequency
D
Frequency doubling indicates lamp outage
D
Two relay driver outputs with high current-carrying
capacity and low saturation voltage
D
Very low susceptibility to EMI
D
Protection according to ISO/TR7637/1 level 4
D
Extremly low current consumption < 10
m
A
(@switches open)
D
Minimum lamp load for flasher operation:
w
1 W
Package
DIP14
SO14
D
Reverse polarity protection
D
Three control inputs: left, right and hazard warning
Ordering Information
Extended Type Number
U2044B
U2044B-FP
Remarks
Pin Description
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Symbol
OSC
SIL
SIR
SIHW
V
S
CR1
CR2
LD
V
S
GND
OR1
V
S
OR2
OSC
Function
Oscillator
Start input left
Start input right
Start input hazard warning
V
S
Control input relay 1
Control input relay 2
Lamp failure detection
V
S
IC ground
Output relay 1
V
S
Output relay 2
Oscillator
OSC
SIL
SIR
SIHW
V
S
CR1
CR2
1
2
3
4
5
6
7
14 OSC
13 OR2
12 Vs
U2044B
11 OR1
10 GND
9
8
V
S
LD
12750
Figure 1. Pinning
TELEFUNKEN Semiconductors
Rev. A1, 25-Feb-97
1 (6)
U2044B
Block Diagram
9
5
+
–
K1
Contact
1
14
R
1
82 k
W
1
+
–
V
Ref1
+
–
+
–
–
+
V
S
–6 V
27.5 V
11
13
GND 10
R
2
220
W
Relay
1
2
3
2
4
R
3
4.7 k
W
R
6
4.7 k
W
R
10
1.2 k
W
–
+
12
V
Ref2
V
S
/2
6
R
9
47 k
W
7
R
8
47 k
W
2
V
S
–81 mV
R
Shunt
30 m
W
30
30
C
1
4.7
m
F
8
30
Hazard warning
R
4
4.7 k
W
right
15
R
5
1.2 k
W
R
7
1.2 k
W
left
31
12700
Figure 2. Application circuit
R
2
for protection against continous reversed polarity: 1 Watt
Functional Description
Pin 1 and Pin 14,
Oscillator
Flashing frequency, f
1
, is determined by the R
1
C
1
components as follows (see figure 2):
f
1
Pin 2 and Pin 3,
Start input right and left
Flashing is disabled as long as the input comparator is tied
zu GND (pull-down resistor R
7
or R
5
). The high side
flasher switch ”left” or ”right” changes the comparator
status and enables the output stage at Pin 11 or Pin 13. R
6
and R
4
are protection resistors for the input stage.
With an open flasher switch the current consumption is
only I 10
m
A. The IC kept in stand-by mode until there
is a voltage drop of V 6.9 V at the pull-down resistor.
Direction mode can only be activated when the ignition
switch is in ON-position as shown in figure 2.
Pin 4,
Start input hazard warnig
In contrast to the direction switches, the hazard input is
[
R
1
1
C
1
C
1
R
1
1.5
Hz
where
47
m
F
+
6.8 k
W
to 510 k
W
In the case of a lamp outage the oscillator frequency is
switched to the lamp outage frequency f
2
with
f
2
2.2 f
1
.
t
[
[
Duty cycle in normal flashing mode: 50%
Duty cycle in lamp outage mode (bright phase): 40%
2 (6)
TELEFUNKEN Semiconductors
Rev. A1, 25-Feb-97
U2044B
a low-side type. The pull-up resistor R
10
provides the off-
state. R
3
is a protection resistor for the input stage.
Hazard warning can be activated independent of the igni-
tion switch position.
Pin 5,
Supply voltage sense
This pin supplies the lamp outage comparator at Pin 8 and
is externally connected to the battery (Kl 30).
Pin 6 and 7,
Control input relay 1 and 2
The feedback detects the bright phase and the dark phase
and enables the oscillator.
Pin 8,
Lamp outage detection
The lamp current is monitored via an external shunt
resistor, R
Shunt
and an internal comparator K1 with its
reference voltage of typ. 81 mV (V
S
= 12 V). The outage
of one lamp out of two lamps is detected according to the
following calculation:
Nominal current of 1 lamp: 21 W / (V
S
= 12 V):
I
lamp
= 1.75 A
Nominal current of 2 lamps: 2 x 21 W / (V
S
= 12 V):
I
lamp
= 3.5 A.
The detection threshold is recommended to be set in the
middle of the current range: I
outage
2.7 A
Thus the shunt resistor is calculated as:
R
Shunt
= V
T
(K1) / I
outage
R
Shunt
= 81 mV/2.7 A = 30 m
W
.
Comparator K1‘s reference voltage is matched to the
characteristics of filament lamps (see “control signal
threshold” in the data part).
The combination of shunt resistor and resistance of wire
harness prevents Pin 8 from a too high voltage in the case
of shortet lamps.
Pin 9,
Supply voltage
This pin supplies the oscillator, the comparators and the
logic parts of the IC.
Pin 10,
GND
The integrated circuit is protected against transients
according to ISO–TR 7637–3 level 3 via resistor R
2
to
ground (–31). An integrated protection circuit together
with external resistors R
2,
R
3,
R
4,
R
6,
R
8
and R
9
limits the
current pulses in the IC. Against reversed battery the IC
is also protected .
Pin 11 and 13,
Control output relay 1 and 2
The relay control outputs are high-side driver with a low
saturation voltage and capable to drive a typical
automotive relay with a coil resistance of 60
W.
Pin 12,
Supply voltage power
This pin supplies the relay drivers connected directly to
the battery (Kl 30). It is internally clamped by a 27-V
Z-diode.
[
Absolute Maximum Ratings
Reference point ground (terminal 31), with external circuitry.
Parameters
Supply voltage, 1 min
Junction temperature
Storage temperature range
Ambient temperature range
Pins 5, 9, 12
Symbol
V
S
T
j
T
stg
T
amb
Value
24
150
–55 to +150
–40 to +100
Unit
V
°C
°C
°C
Thermal Resistance
Parameters
Junction ambient
DIP14
SO14
Symbol
R
thJA
R
thJA
Value
90
120
Unit
K/W
K/W
TELEFUNKEN Semiconductors
Rev. A1, 25-Feb-97
3 (6)
U2044B
Electrical Characteristics
Typical values under normal operation in application circuit figure 1, V
S
(+30) = 12 V.
Reference point ground (–31), T
amb
= 25°C, unless otherwise specified.
Parameters
Supply voltage range
Supply current,
switches open
Output current for relay
driver
Saturation voltage
Test Conditions / Pins
Pins 5, 9, 12
Pins 5, 9, 12
Pins 11, 13
R
L
= 82
W
V
S
= 8 V
V
S
= 12 V
Pins 11, 13
V
O
R
L
I
O
t
ON
V
S
= 9 V
Pin 8
V
S
= 13.5 V
V
S
= 16 V
V
S
= 9 to 16 V, Pin 8
T
amb
= –40 to +100°C
V
S
= 13.5 V
Pin 8
T
amb
= –40 to +100°C
T
amb
= –40 to +100°C
V
S
70.6
85.0
93.0
–6
T
K
V
12
V
12
25.0
18
10
27.5
20
30.0
22
+6
60
0.1
10
1.0
1.2
Symbol
V
S
I
S
I
O
Min.
8
Typ.
Max.
18
10
300
Unit
V
m
A
mA
Relay coil resistance
Relay output,
reverse current
Start delay
(first bright phase)
Control signal threshold
W
mA
ms
mV
mV
mV
%
m
V/K
V
V
V
V
Pins 11, 13
Tolerance of control signal
threshold
Temperature coefficient of
control signal threshold
Clamping voltage
Relay output overvoltage
detection (relay disabled)
Tolerances
V
S
= 9 to 18 V, T
amb
= –40 to +100°C
Parameters
Frequency determining
resistor
Frequency determining
capacitor
Frequency tolerance
(normal flashing basic fre-
quency f
1
not including the
tolerance of the external
components R
1
and C
1
)
Bright period (basic fre-
quency f
1
)
Bright period
(control frequency f
2
)
Frequency increase
(lamp failure)
Lamp load
Test Conditions / Pins
Symbol
R
1
C
1
Min.
6.8
Typ.
Max.
510
47
–5
+5
Unit
k
W
m
F
%
D
f
1
D
F
1
D
f
2
f
2
P
L
47
37
2.15
f
1
2.3
53
45
f
1
%
%
Hz
W
1
4 (6)
TELEFUNKEN Semiconductors
Rev. A1, 25-Feb-97
U2044B
Package Information
Package DIP14
Dimensions in mm
20.0 max
7.77
7.47
4.8 max
6.4 max
0.5 min 3.3
0.36 max
1.64
1.44
0.58
0.48
15.24
14
8
2.54
9.8
8.2
technical drawings
according to DIN
specifications
13020
1
7
Package SO14
Dimensions in mm
5.2
4.8
8.75
3.7
1.4
0.4
1.27
7.62
14
8
0.25
0.10
0.2
3.8
6.15
5.85
technical drawings
according to DIN
specifications
13035
14
8
TELEFUNKEN Semiconductors
Rev. A1, 25-Feb-97
5 (6)
Analog electronics
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