Maker : TEMIC Semiconductors
Part No. : U2043B

  Datasheet PDF : U2043B.pdf
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Shortcut : U2043B  U2043B  U2043B-FP 

Product Information

U2043B Flasher, 30-mW Shunt, Pilot Lamp to GND or VBatt Description The integrated circuit U2043B is used in relay controlled automotive flashers where a high EMC level is required. A lamp outage is indicated by frequency doubling during hazard mode as well as direction mode. Pilot lamp can be connected either to VBatt or GND. Features 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 D Minimum lamp load for flasher operation w 10 W Package DIP8 SO8 D Low susceptibility to EMI Ordering Information Extended Type Number U2043B U2043B–FP Remarks Block Diagram + VS + 49 6 C1 Measuring comparator 4 K 1 V 6–81 mV 7 Pilot lamp Pulse generator 3.8 k W 8 K 3 V –5 V 6 49 a–Comparator 23 V 1 IC Ground 13283 2 R3 Shunt 30 m W 5W R1 3 Relay R2 3.3 k W 49 a 5 R1 100 W GND – 31 5 W 21 W 21 W 21 W 21 W 5 W Indicator lamps Pilot lamps Figure 1. TELEFUNKEN Semiconductors Rev. A2, 25-Feb-97 1 (6) U2043B Pin Description Pin 1 2 3 4 5 6 7 8 Symbol GND VS REL OSC OSC VS LD SI Function IC ground Supply voltage VS Relay driver C1 oscillator R1 oscillator Supply voltage VS Lamp failure detection Start input (49a) GND Vs REL OSC 1 2 8 7 SI LD Vs OSC 12749 U2043B 3 4 6 5 Figure 2. Pinning Functional Description Pin 1, GND The integrated circuit is protected against damage via resistor R4 to ground (–31) in the case of battery reversal. An integrated protection circuit together with external resistances R2 and R4 limits the current pulses in the IC. Pin 2, Supply voltage, VS - Power The arrangement of the supply connections to Pin 2 must be such as ensure that, on the connection printed circuit board (PCB), the resistance of VS to Pin 6 is lower than that to Pin 2. Pin 3, Relay control output (driver) The relay control output is a high-side driver with a low saturation voltage and capable to drive a typical automotive relay with a minimum coil resistance of 60 W. Pin 4 and 5 Oscillator Flashing frequency, f1, is determined by the R1C1 components as follows (see figure 1): mized layer resistance from point VS / shunt to Pin 6 is recommended. Pin 7, Lamp outage detection The lamp current is monitored via an external shunt resistor R3 and an internal comparator K1 with its reference voltage of typ. 81 mV (VS = 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 / (VS = 12 V): Ilamp = 1.75 A Nominal current of 2 lamps: 2 x 21 W / (VS = 12 V): Ilamp = 3.5 A. The detection threshold is recommended to be set in the middle of the current range: Ioutage 2.7 A Thus the shunt resistor is calculated as: R3 = VT (K1) / Ioutage R3 = 81 mV/2.7 A = 30 mW. 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 7 from a too high voltage in the case of shortet lamps. [ where [ R C1 1.5 Hz C  47 mF R + 6.8 kW to 510 kW f1 1 1 1 1 In the case of a lamp outage (see Pin 7) the oscillator frequency is switched to the lamp outage frequency f2 with f2 2.2 f1. [ Duty cycle in normal flashing mode: 50% Duty cycle in lamp outage mode: 40% (bright phase) Pin 6, Supply voltage, Sense For accurate monitoring via the shunt resistor, a mini- Pin 8, Start input Start condition for flashing: the voltage at Pin 8 has to be below less than VS – 5 V (flasher switch closed). Humidity and dirt may decrease the resistance between 49 a and GND. If this leakage resistance is 5 kW the IC is still kept in its off-condition. In this case the voltage at Pin 8 is greater than VS – 5 V. During the bright phase the voltage at Pin 8 is above the K2 threshold, during the dark phase it is below the K3 threshold. For proper start conditions a minimum lamp wattage of 10 W is requir...

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