U4791B
Automotive Lamp Outage Monitor, VT = 53 mV
Description
The monolithic integrated bipolar circuit, U4791B, is desi...
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...