U2043B

Features Temperature and Voltage Compensated Frequency Warning Indication of Lamp Failure by Means of Frequency Doubling Minimum Lamp Load for Flasher Operation ≥ 10W Relay Output with High Current Carrying Capacity and Low Saturation Voltage Low Susceptibility to EMI www.DataSheet4U.com 1. 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. The pilot lamp can be connected either to VBatt or GND. Figure 1-1. Block Diagram +VS + 49 6 C1 Measuring comparator 4 K 1 V 6-81 mV 7 Pilot lamp Pulse generator 3.8 k Ω 8 K 3 V 6-5 V 49 a-Comparator 23 V 1 IC Ground R1 100 Ω GND - 31 5 W 21 W 21 W 21 W Indicator lamps Pilot lamps 21 W 5 W 3 Relay R2 3.3 k Ω 49 a 5W 2 R3 Shunt 30 m Ω Flasher, 30 mΩ Shunt, Pilot Lamp to GND or VBatt U2043B R1 5 Rev. 4720B–AUTO–09/05 2. Pin Configuration Figure 2-1. Pinning DIP8/SO8 GND 1 2 8 7 SI VS REL www.DataSheet4U.com LD VS OSC U2043B 3 4 6 5 OSC Table 2-1. Pin 1 2 3 4 5 6 7 8 Pin Description 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) 2 U2043B 4720B–AUTO–09/05 U2043B 3. Functional Description 3.1 GND (Pin 1) The integrated circuit is protected against damage via resistor R4 to ground (–31) in the case of battery reversal. An int...