U4791B
Automotive Lamp Outage Monitor, V
T
= 53 mV
Description
The monolithic integrated bipolar circuit, U4791B, is de-
signed 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 V
4,6
= V
S
– V
T
whereas
V
T
= 53 mV.
The integrated circuit is recommended for the application
of parallel connected lamps. If the voltage drop across
shunt resistor, R
sh
, 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
V
S
2
R
sh
Z
2
–
+
0.6 V
S
8
–
+
6
Z
3
1
Lamps
R
1
150
W
3
&
OUT2
&
Z
5
–
+
7
5
V
Batt
OUT1
4
R
sh
95 10613
Figure 1. Schematic and application circuit
TELEFUNKEN Semiconductors
Rev. A2, 17-Dec-96
1 (5)
TEMIC [ TEMIC SEMICONDUCTORS ]
