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U243B
Warning or Car-Direction Indicator
Technology: Bipolar Features
D Can be protected against damage or interference with
a minimum of external circuitry
D Voltage dependence of the car indicator lamps also
compensated for lamp failure
D Temperature- and voltage-compensated frequency D Warning indication of lamp failure by means of
frequency doubling
D Relay output with high-current carrying capacity and
low saturation voltage
Figure 1. Application circuit as a car flasher (Resistor R1, R2 and Rt: 1/4 Watt R1 for protection against continuous reversed polarity: 2 Watt)
Order Information
Extended Type Number U243B U243B-FP Package 8 pin dual-inline plastic 8 pin SO plastic Remarks
TELEFUNKEN Semiconductors Rev. A1, 05-Sep-96
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Preliminary Information
U243B
Circuit Description
The application circuit shows the operation of the U243B as a car-direction indicator signal generator. The flashing frequency is determined by the components Rt and Ct, and the frequency can be calculated from f1 The use of this application circuit ensures damage and interference protection accordance to VDE 0839. The recognition point for lamp failure can be calculated from the control signal threshold, typically 81 mV with VS = 12 V. With 81 mV and a measuring resistance of R3 = 30 mW, it corresponds to a lamp current of 2.7 A, i.e., the frequency change-over with a lamp load of 21 W + 11.4 W. The variation of the control-signal threshold with the supply voltage takes into account the PTC characteristic of the filament lamps. A resistance Rp 5 kW between the lamp indicator (49a) and ground (31) ensures that in case the direction indicator switch is open, the flashing generator is in stand-by mode. With a control lamp of max. 4 W between 49 and 49a the IC still starts with the bright phase. The arrangement of the supply connections to Pins 2 and 6 must be such as to ensure that, on the connection PCB, the resistance of VS to Pin 6 is lower than that to Pin 2. Defined operation is ensured with a lamp load of PL 10 W or more. Defined operation with lamp loads 2 W require an additional external resistance as described in "Applications". With considerably reduced external circuitry, the integrated circuit U243B can be used as an instable multivibrator in the frequency range f = 0.05 to 10 Hz.
1 Rt Ct 1.5
(Hz)
where f1 is the frequency in normal flashing operation (basic frequency). The control frequency f2 is typically 2.2 times the value of f1 and is the frequency in the case of lamp failure. The bright periods for f1 and f2 are internally set in the IC and are 50% for f1 and 40% for f2. The resistors R1 and R2 are needed to protect the circuit against possible damage. An integrated Z-diode in addition to these external resistors limits the impulse current in the integrated circuit to 1.5 A. Connecting the circuit with the wrong polarity leads to current limitation by R1, R2 and the resistance of the coil of the relay. A current of about 150 mA would then flow over R1, so that for unlimited protection against continuous reversal of the polarity of the supply, a 2-W resistor would be necessary. A short circuit between the indicator lamp (49a) and ground (31) can give rise to a voltage drop of about 4 V across the measuring resistance, R3. The circuit is not damaged by such a short circuit.
Absolute Maximum Ratings
Reference point Pin 1 Parameters Supply voltage Surge forward current tp = 0.1 ms tp = 2 ms tp = 2 ms Output current Power dissipation Tamb = 95C Tamb = 60C Junction temperature Ambient temperature range Storage temperature range Pins 2 and 6 Pins 2 and 6 Pins 2 and 6 Pin 8 Pin 3 DIP8 SO8 DIP8 SO8 Symbol VS IFSM IFSM IFSM Io Ptot Ptot Ptot Ptot Tj Tamb Tstg Value 16.5 1.5 1.0 50 0.3 420 340 690 560 150 -40 to +95 -55 to +125 Unit V A A mA A mW mW mW mW C C C
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Preliminary Information
TELEFUNKEN Semiconductors Rev. A1, 05-Sep-96
U243B
Electrical Characteristics
Typical values under normal operation in application circuit figure 1, VS (+49, Pins 2 and 6) = 12 V Reference point ground (-31), Tamb = 25C, unless otherwise specified Parameters Test Conditions / Pin Supply voltage range Pins 2 and 6 Supply current, Pins 2 and 6 dark phase or stand-by Supply current, Pins 2 and 6 bright phase Z-diode limitation IS2, 6 = 70 mA Pins 2 and 6 Relay output, saturation voltage I0 = 150 mA, VS = 9 V Pin 3 Relay output, Pin 3 reverse current Relay coil resistance Start delay (first bright phase) Frequency-determining resistor Frequency-determining capacitor Frequency tolerance (normal flashing, basic frequency f1 not including the tolerance of the external components R1 and Ct) Bright period (basic frequency f1) Bright period (control frequency f2) Frequency increase (lamp failure) Control-signal threshold VS = 15 V Pin 7 VS = 9 V Pin 7 VS = 12 V Pin 7 Transfer resistance 49a to common for stand-by Lamp load Symbol VS (+49) IS IS VS Min Typ 9 ... 15 4.5 7.0 23 Max Unit V mA mA V
8 11
VO IO RL ton Rt Ct f1 f1 f2 f2 VR3 VR3 VR3 RP PL 10 6.8
1.0 0.1 60 10 510 47
V mA
W
ms kW
mF
% % %
-5 47 37 2.15 f1 85 66 76 91 71 81 2
+5 53 45 2.3f1 97 76 87 5
mV mV mV kW W
Applications
D Flashing generator, operation with smaller loads
( 2 W) By adding a resistor to the application circuit (figure 1), defined operation with lamp loads 2 W is possible. The voltage drop across the resistor R4 is generated by the current flowing over the relay and should be about 15 mV. With a relay current of 150 mA (relay resistance 73 Q), this requires a resistance of R4 = 100 mW. The change of TELEFUNKEN Semiconductors Rev. A1, 05-Sep-96 the operating point by 15 mV results in a corresponding change of the control signal threshold by 15 mV. For a lamp current of 2.7 A, a measuring resistance of R3 = 81 mV - 15 mV 2.7 A = 25 mW results.
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Preliminary Information
U243B
D Istable multivibrator
The figure shows the minimum of circuitry necessary for the operation as an instable multivibrator. The circuit is suitable for frequencies between 0.05 Hz and approximately 10 kHz. The frequency can be calculated by using the relationship for f1 given in circuit description. A starting resistor of 3.8 kW is integrated into the circuit between pins 8 and 6. This means that, for a load on pin 3 of, for example, 500 W (open circuits) and zero current, a voltage of about 1.4 V remains on the load (for 70 WWthe corresponding voltage is about 220 mV). A load of RL 3.3 kW on pin 3 ensures correct operation of the instable multivibrator. The relationship between the on- and offperiods can be changed in this circuit by inserting a resistor-diode combination parallel to R1 (see dashed lines in the figure), e.g., to reduce the "bright"-time.
Figure 2. Flashing generator with small loads
Figure 3. Instable multivibrator for general-purpose applications
Pin Description
Pin 1 2 3 4 Function IC ground Supply voltage VS Relay driver Ct oscillator Pin 5 6 7 8 Function Rt oscillator Supply voltage VS Lamp-failure detection Start input (49a)
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Preliminary Information
TELEFUNKEN Semiconductors Rev. A1, 05-Sep-96
U243B
Dimensions in mm
Package: DIP8
Package: SO8 (SOT96A)
TELEFUNKEN Semiconductors Rev. A1, 05-Sep-96
5 (6)
Preliminary Information
U243B
Ozone Depleting Substances Policy Statement
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
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Preliminary Information
TELEFUNKEN Semiconductors Rev. A1, 05-Sep-96

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