U642B
Interval- and Wipe/ Wash Wiper Control IC
Description
As a convenience feature of the windshield wiper
intermittent and wipe/wash operation are implemented in
most of the automobiles. The U642B is the low-cost
solution for an accurate timing function control.
Wipe/wash mode has priority over interval mode. Interval
pause and afterwiping time can be set to fixed values by
using resistors in a broad time range. Added value can be
provided with an individual, continuous adjustment of the
interval pause by a potentiometer which may be built into
the stalk. For proper operation it is mandatory to feed the
signal of the wiper motor‘s park switch into U642B.
Features
D
Interval pause: 4 to 20 s
D
Afterwiping time: 2 to 20 s
D
Wiper motor’s park switch
D
Wipe/wash mode priority
D
One external capacitor, determines all time sequences
D
Relay driver with Z-diode
D
Interference protection according to VDE 0839 or
ISO/TR 7637/1
D
Load-dump protected
Block Diagram
VS
8
OUT
7
PARK
6
VRef
Park switch
comparator
WASH
5
VRef
Input
comparator
Load-dump
comparator
VRef
Logic
VRef
Interval
comparator
Wipe / wash
comparator
A
B
C
D
E
F
1
GND
2
INT
3
C
t
R
t
4
94 8950
Figure 1. Block diagram
Rev. A4, 10-Apr-01
1 (7)
ATMEL [ ATMEL CORPORATION ]
