Maker : ATMEL Corporation
Part No. : U2044B

  Datasheet PDF : U2044B.pdf
  Cross Reference : U2044B Cross Reference
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Shortcut : U2044B  U2044B  U2044B-FP 

Product Information

Features • Temperature and Supply Voltage Compensated Flashing Frequency • Frequency Doubling Indicates Lamp Outage • Two Relay Driver Outputs with High Current-carrying Capacity and Low Saturation • • • • • • Voltage Minimum Lamp Load for Flasher Operation: ³ 1 W Very Low Susceptibility to EMI Protection According to ISO/TR7637/1 Level 4 Extremly Low Current Consumption < 10 µA (with Switches Open) Reverse Polarity Protection Three Control Inputs: Left, Right and Hazard Warning Dual Output Flasher U2044B www.DataSheet4U.com 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 indicated by frequency doubling during direction mode. Thanks to extreme low current consumption the U2044B can be directly connected to the battery. Rev. 4721A–AUTO–05/03 1 Figure 1. Block Diagram 30 9 5 RShunt C1 4.7 µF K1 Contact 1 14 R1 82 k W + V Ref1 1 + 7 + + V S-6 V 27.5 V 11 13 GND R2 220 W Hazard warning R4 4.7 k W R6 4.7 k W right 10 3 2 4 R3 4.7 k W R10 1.2 k W + 12 V Ref2 V S /2 6 R9 47 k W R8 47 k W 2 + V S-81 mV 8 30 m W 30 www.DataSheet4U.com 30 Relay 1 2 15 left 31 12700 R5 1.2 k W R7 1.2 k W 2 U2044B 4721A–AUTO–05/03 U2044B Pin Configuration Figure 2. Pinning DIP14/SO14 OSC 1 SIL 2 SIR 3 14 OSC 13 OR2 12 VS SIHW 4 www.DataSheet4U.com U2044B 11 OR1 10 GND 9 8 VS LD VS 5 CR1 6 CR2 7 Pin Description Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Symbol OSC SIL SIR SIHW VS CR1 CR2 LD VS GND OR1 VS OR2 OSC Function Oscillator Start input left Start input right Start input hazard warning VS Control input relay 1 Control input relay 2 Lamp failure detection VS IC ground Output relay 1 VS Output relay 2 Oscillator 3 4721A–AUTO–05/03 Functional Description Oscillator (Pin 1 and 14) Flashing frequency, f1, is determined by the R1C1 components as follows (see Figure 1): 1 f 1 » ---------------------------------- Hz R 1 ´ C 1 ´ 1.5 where C1 £ 47 µF R1 = 6.8 kW to 180 kW www.DataSheet4U.com In the case of a lamp outage, the oscillator frequency is switched to the lamp outage frequency f2 with f2 » 2.2 ´ f1. Duty cycle in normal flashing mode: Duty cycle in lamp outage mode: 50% 40% (bright phase) Start Input Right and Left Flashing is disabled as long as the input comparator is tied to GND (pull-down resistor R7 or R5). The high-side flasher switch left or right changes the comparator status and (Pin 2 and 3) enables the output stage at pin 11 or Pin 13. R6 and R4 are protection resistors for the input stage. With an open flasher switch the current consumption is only I < 10 µA. The IC is 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 the ON-position as shown in Figure 1. Start Input Hazard Warning (Pin 4) Supply Voltage Sense (Pin 5) Control Input Relay 1 and 2 (Pin 6 and 7) Lamp Outage Detection (Pin 8) In contrast to the direction switches, the hazard input is a low-side type. The pull-up resistor R10 provides the off-state. R3 is a protection resistor for the input stage. Hazard warning can be activated independent of the ignition switch position. This pin supplies the lamp outage comparator at pin 8 and is externally connected to the battery (Kl 30). The feedback detects the bright phase and the dark phase and enables the oscillator. The lamp current is monitored via an external shunt resistor, RShunt and an internal comparator, K1, with its reference voltage of typically 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): Nominal curr...

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