UAA1041B Automotive Direction Indicator Flahser IC

Description

LD1041 (analog UAA1041B) was designed for use in conjunction with a relay in automotive applications. It is also applicable for other warning lamps such as hand brake ON  etc.

Features Ordering Information

• Defective Lamp Detection
• Over voltage Protection
• Reverse Battery Connection Protection
• Integrated Suppression Clamp Diode
• Short Circuit Detection and Relay Shutdown to Prevent Risk of Fire

Circuit Description

The circuit is designed to drive the direction indicator flasher relay. Figure 1 shows the typical system configuration with the external components. It consists of a network (R1, C1) to determine the oscillator frequency, shunt resistor (RS) to detect defective bulbs and short circuits in the system, and two current limiting resistors (R2 / R3) to protect the IC against load dump transients. The circuit can be used either with or without short circuit detection, and features overvoltage, defective lamp and short circuit detection. The light bulbs L1, L2, L3, L4 are the turn signal indicators. When switch K1 is closed, after a time delay of t1 (in our example t1 75 ms), the relay will be actuated. The corresponding light bulbs (L1, L2 or L3, L4) will flash at the oscillator frequency, independent of the battery voltage of 8.0V to 18V. The flashing cycle stops and the circuit is reset to the initial position when switch K1 is open.