U479B
Automotive Lamp Outage Monitor, V
T
= 8 mV
Description
The monolithic integrated bipolar circuit, U479B, 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 V
4,6
= V
S
– V
T
whereas V
T
= 8 mV.
If the voltage drop across shunt resistor, R
sh
, exceeds
8 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 input must be
connected to Pin 7.
Features
D
D
D
D
2 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
U479B
U479B–FP
Package
DIP8
SO8
Remarks
Block Diagram
V
S
2
R
sh
Z
2
–
+
0.6 V
S
–
+
8
–
+
6
1
Lamps
R
1
150
W
95 10380
V
Batt
7
5
&
OUT1
4
R
sh
3
&
OUT2
Figure 1. Schematic and application circuit
TELEFUNKEN Semiconductors
Rev. A2, 04-Feb-97
1 (5)
TEMIC [ TEMIC SEMICONDUCTORS ]
