U4791B

U4791B Automotive Lamp Outage Monitor, VT = 53 mV Description The monolithic integrated bipolar circuit, U4791B, is designed as a monitor for lamp failure in automobiles. The comparator threshold is matched to the PTC characteristic of incandescent lamps. The threshold is tied to a typical value of V4,6 = VS – VT whereas VT = 53 mV. The integrated circuit is recommended for the application of parallel connected lamps. If the voltage drop across shunt resistor, Rsh, exceeds 53 mV, the output is turned off, otherwise the output is turned on. Without supply voltage or open input Pin 8 the output is turned off. A not used comparator must be connected to Pin 7. Features D D D D 10 kV–ESD protection Two comparators with common reference Tight threshold tolerance Threshold matched to PTC characteristic of incandescent lamps D NPN output D Interference and damage–protection according to VDE 0839 D Temperature compensated D EMI protection D Reversal polarity protection D Load-dump protection Ordering Information Extended Type Number U4791B U4791B–FP Package DIP8 SO8 Remarks Block Diagram VS 2 Rsh Z2 – + 0.6 VS 8 – + 6 Z3 1 Lamps R1 150 W 3 & OUT2 & Z5 – + 7 5 VBatt OUT1 4 Rsh 95 10613 Figure 1. Schematic and application circuit TELEFUNKEN Semiconductors Rev. A2, 17-Dec-96 1 (5) U4791B Pin Description Input switch VRef IN2 OUT1 Pin 1 2 3 4 5 6 7 8 Symbol GND VS OUT2 IN1 OUT1 IN2 VRef Input Function Reference point, ground Supply voltage Output 2 Input 1 Output 1 Input 2 Re...