U643B
Flasher, 30-mW Shunt
Description
Bipolar integrated circuit, U643B, is used in relay- Lamp outage is indicated by frequency doubling during
controlled automotive flashers where a high level EMC hazard warning as well as direction mode.
is required.
Features
D Temperature and supply voltage compensated flash- D Minimum lamp load for flasher operation: ≥ 1 W
ing frequency
D Very low susceptibility to EMI
D Frequency doubling indicates lamp outage
D Protection according to ISO/TR 7637/1 level 4
D Relay driver output with high current carrying
capacity and low saturation voltage
Ordering Information
Extended Type Number Package Remarks
U643B DIP8
U643B-FP SO8
Block Diagram
+ VS
+ 49
6 2
30 mW
C1 R3
Measuring comparator K 1
Shunt
V6–81 mV
4 20 kW 5 kW
K1 7
K2
Pulse 3
R1
generator
49 a–Comparator K2 Relay
20 kW
49 a–Comparator K3 8 R2
49 a
K3 1.5...2.2 kW
5 23 V
20 kW 5 kW
IC Ground
1
R4
95 9756
470 W 5 W 21 W 21 W 21 W 21 W 5 W
Indicator lamps
GND
– 31
Figure 1. Application circuit as a car flasher
Resistor R1, R2 and R4: 1/4 Watt
R4 for protection against continuous reversed polarity: 0.5 Watt
TELEFUNKEN Semiconductors 1 (5)
Rev. A1, 25-Feb-97
U643B
Pin Description
Pin Symbol Function GND 1 8 SI
1 GND IC ground
2 VS Supply voltage VS VS 2 7 LD
3 REL Relay driver U643B
4 OSC C1 Oscillator
REL 3 6 Vs
5 OSC R1 Oscillator
6 VS Supply voltage VS
OSC 4 5 OSC
7 LD Lamp failure detection
8 SI Start input (49a) 94 9290
Figure 2. Pinning
Functional Description
Pin 1, GND mized layer resistance from point VS / shunt to Pin 6 is
The integrated circuit is protected against damage via recommended.
resistor R4 to ground (–31) in the case of battery reversal.
Pin 7, Lamp outage detection
An integrated protection circuit together with external
The lamp current is monitored via an external shunt
resistances R2 and R4 limits the current pulses in the IC.
resistor R3 and an internal comparator K1 with its
reference voltage of typ. 81 mV (VS = 12 V). The outage
Pin 2, Supply voltage, VS - Power
of one lamp out of two lamps is detected according to the
The arrangement of the supply connections to Pin 2 must
following calculation:
be such as ensure that, on the connection printed circuit
Nominal current of 1 lamp: 21 W / (VS = 12 V):
board (PCB), the resistance of VS to Pin 6 is lower than
Ilamp = 1.75 A
that to Pin 2.
Nominal current of 2 lamps: 2 x 21 W / (VS = 12 V):
Ilamp = 3.5 A.
Pin 3, Relay control output (driver)
[
The detection threshold is recommended to be set in the
The relay control output is a high-side driver with a low
middle of the current range: Ioutage 2.7 A
saturation voltage and capable to drive a typical automo-
tive relay with a minimum coil resistance of 60 W.
Thus the shunt resistor is calculated as:
R3 = VT (K1) / Ioutage
R3 = 81 mV/2.7 A = 30 mW.
Pin 4 and 5 Oscillator
Comparator K1‘s reference voltage is matched to the
Flashing frequency, f1, is determined by the R1C1 compo-
characteristics of filament lamps (see “control signal
nents as follows (see figure 1):
threshold” in the data part).
[R
The combination of shunt resistor and resistance of wire
f1 1 Hz harness prevents Pin 7 from a too high voltage in the case
1 C1 1.5
of shortet lamps.
47 mF
+ 6.8 kW to 510 kW
where C1 Pin 8, Start input
R1 Start condition for flashing: the voltage at Pin 8 has to be
below K3 threshold (flasher switch closed).
u
In the case of a lamp outage (see Pin 7) the oscillator Humidity and dirt may decrease the resistance between
49 a and GND. If this leakage resistance is 5 kW the IC
[
frequency is switched to the lamp outage frequency f2
with f2 2.2 f1. is still kept in its off-condition. In this case the voltage at
Pin 8 is between the thresholds of comparators K2 and
Duty cycle in normal flashing mode: 50% K3.
Duty cycle in lamp outage mode: 40% (bright phase) During the bright phase the voltage at Pin 8 is above the
K2 threshold, during the dark phase it is below the K3
Pin 6, Supply voltage, Sense threshold. For proper start conditions a minimum lamp
For accurate monitoring via the shunt resistor, a mini- wattage of 1 W is required.
2 (5) TELEFUNKEN Semiconductors
Rev. A1, 25-Feb-97
U643B
Absolute Maximum Ratings
Reference point Pin 1
Parameters Symbol Value Unit
Supply voltage Pin 2 and 6 VS 16.5 V
Surge forward current
tP = 0.
0.1 mss Pin 2 aand
d6 IFSM 1.5
.5 A
tP = 300 ms Pin 2 and 6 IFSM 1.0 A
tP = 300 ms Pin 8 IFSM 50 mA
Output current Pin 3 IO 0.3 A
Power dissipation
Tamb = 95°C DIP 8 Ptot 420 mW
SO 8 Ptot 340 mW
Tamb = 60°C DIP 8 Ptot 690 mW
SO 8 Ptot 560 mW
Junction temperature TJ 150 °C
Ambient temperature range Tamb –40 ... + 95 °C
Storage temperature range Tstg –55 ... + 150 °C
Thermal Resistance
Parameters Symbol Value Unit
Junction ambient DIP8 RthJA 110 K/W
SO8 RthJA 160 K/W
Electrical Characteristics
Typical values under normal operation in application circuit (see figure 1), VS (+49, Pin 2 and 6) = 12 V.
Reference point ground (–31), Tamb = 25°C, unless otherwise specified
Parameters Test Conditions / Pins Symbol Min. Typ. Max. Unit
Supply voltage range Pin 2 and 6 VS (+49) 9 to 15 V
Supply current: Pin 2 and 6
Dark phase IS 4.5
45 8 mA
Bright phase IS 7.0 11 mA
Relay output: Pin 3
saturation voltage IO = 150 mA, VS= 9 V
with resistance = 60 W VO 1.0 V
reverse current IO 0.1 mA
Start delay First bright phase ton 10 ms
Frequency tolerance df 1 –5 +5 %
Bright period Basic frequency f1 ∆f1 47 53 %
Control frequency f2 ∆f2 37 45 %
Frequency increase Lamp outage f2 2.15 f1 2.3 f1 Hz
Control signal threshold VS = 15 V Pin 7 VR3 85 91 97 mV
VS = 9 V Pin 7 VR3 66 71 76 mV
VS = 12 V Pin 7 VR3 76 81 87 mV
Leakage resistance 49a to GND RP 4 5 kW
Lamp load PL 1 W
TELEFUNKEN Semiconductors 3 (5)
Rev. A1, 25-Feb-97
U643B
Package Information
Package DIP8
Dimensions in mm 9.8 7.77
9.5 7.47
1.64
1.44
4.8 max
6.4 max
0.5 min 3.3
0.36 max
0.58 9.8
0.48 2.54 8.2
7.62
8 5
technical drawings
according to DIN
specifications
13021
1 4
Package SO8
Dimensions in mm
5.2
4.8
5.00
4.85 3.7
1.4
0.25 0.2
0.4 3.8
0.10
1.27 6.15
3.81 5.85
8 5
technical drawings
according to DIN
specifications
13034
8 5
4 (5) TELEFUNKEN Semiconductors
Rev. A1, 25-Feb-97
U643B
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It is the policy of TEMIC TELEFUNKEN microelectronic GmbH to
1. Meet all present and future national and international statutory requirements.
2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems
with respect to their impact on the health and safety of our employees and the public, as well as their impact on
the environment.
It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as
ozone depleting substances ( ODSs).
The Montreal Protocol ( 1987) and its London Amendments ( 1990) intend to severely restrict the use of ODSs and
forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban
on these substances.
TEMIC TELEFUNKEN microelectronic GmbH semiconductor division has been able to use its policy of
continuous improvements to eliminate the use of ODSs listed in the following documents.
1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively
2 . Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental
Protection Agency ( EPA) in the USA
3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C ( transitional substances ) respectively.
TEMIC can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain
such substances.
We reserve the right to make changes to improve technical design and may do so without further notice.
Parameters can vary in different applications. All operating parameters must be validated for each customer
application by the customer. Should the buyer use TEMIC products for any unintended or unauthorized
application, the buyer shall indemnify TEMIC against all claims, costs, damages, and expenses, arising out of,
directly or indirectly, any claim of personal damage, injury or death associated with such unintended or
unauthorized use.
TEMIC TELEFUNKEN microelectronic GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany
Telephone: 49 ( 0 ) 7131 67 2831, Fax number: 49 ( 0 ) 7131 67 2423
TELEFUNKEN Semiconductors 5 (5)
Rev. A1, 25-Feb-97
