a
FEATURES
Continuous Status Checks of Five Bulbs
Lamp Status Check in 鈥淥N鈥?and 鈥淥FF鈥?States
Status Checks of Two In-Line Fuses
Very Low Voltage Drop at Sensor Shunt Resistor
(Comparator Threshold 1.75 mV at 22 C)
Temperature and Supply Voltage Compensated
Powered Directly from Car Battery: Protection
Included for Transient, Reverse Supply, Load Dump
Operating Temperature Range: 鈥?0 C to +125 C
15 V CMOS Compatible Digital Output Signals
Voltage Limited Power Supply Output for 15 V CMOS
Logic ICs
5-Channel Monolithic Comparator
for Lamp Monitoring
AD22001*
FUNCTIONAL BLOCK DIAGRAM
POWER
OUT
+V
S
2
SWITCH &
LIMITER
3
CHIP 1
ENABLE
GND
20
AD22001
CHANNEL 1
鈥揑N1
4
+IN1 5
IN
FUSE
1 & 2 6
鈥揑N2
+IN2
9
8
CHANNEL 2
7
OUT 1 & 2
鈥揑N3 11
+IN3 10
CHANNEL 3
13
12
OUT 3 & 4
OUT (3
脳
4)
GENERAL DESCRIPTION
The AD22001 is a monolithic, five-channel comparator circuit
for monitoring the functionality of lamps in automotive
applications.
The IC tests the series circuit leading to the lamp to determine
if the circuit is intact and a functional lamp is in the socket. The
AD22001 continuously checks the functionality of up to five
bulbs in either their 鈥渙n鈥?or 鈥渙ff鈥?state, and also tests for the
presence of an in-line fuse in two of the series circuits.
Digital outputs indicate the status of each channel. Additionally,
the AD22001 provides a voltage limited power supply output to
supply 15 V CMOS circuits that may interface to the AD22001.
鈥揑N4 14
+IN4 15
CHANNEL 4
CHANNEL 5
鈥揑N5 16
+IN5 17
IN
FUSE
5 19
18
OUT 5
FUSE
+V BATT
SWITCH
OUTPUT
COPPER
SHUNT
RESISTOR
LAMP
SIGNAL CONDITIONING
AND SIGNAL PROCESSING
Figure 1. Typical Application Circuit for a Single Channel Lamp Monitor
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
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