U641B_05 ATMEL [ATMEL Corporation], U641B_05 Datasheet - Page 4

• Manufacturer Part Number: U641B_05
• Description: Interval and Wipe/Wash Wiper Control IC with Delay
• Manufacturer: ATMEL [ATMEL Corporation]

4. Circuit Description
4.1
4.2
4.3
4
Interval Function, Pin 2
Wipe/Wash (WIWA) Operation, Pin 5
Interval and WIWA Functions
U641B
By closing the interval switch, S
rent source (pin 3) which holds the capacitor C
there is a positive potential at the park switch (S
charges the capacitor C
potential, the relay is in the off position - interval pause begins - the capacitor C
through the current source C, till the voltage at pin 3 is below the threshold of 2V. Interval pause
can be adjusted between 4 s to 20 s with the help of potentiometer R
on and the next interval cycle begins. Opening switch S
C
By closing the WIWA switch, S
water on the windshield. During this function, the current source A is switched-off which keeps
the capacitor C
F. If (after a time interval of approximately 600 ms) the voltage at the capacitor is greater than
6.1V, the relay is turned on as long as the switch WIWA is closed.
The after-wiping time begins when the switch is open, the sources D and F are switched off and
the source E is activated. Source E discharges the capacitor until the voltage is less than 2.2V.
The relay is off and the wiper-motor is supplied via the park switch until the park position is
reached. The after-wiping time is determined by the current source E which can be regulated
with the external resistor R
charges the capacitor. The relay switch is independent of the park switch S
The interval function is interrupted immediately when the switch S
source A discharges the capacitor to a value of 2V, afterwards, the normal wash function starts.
Interval wiping starts immediately when the after-wipe time is over. The switching delays are
slightly shorter, because the capacitor is already charged to a value of 2V.
The Wipe/Wash function is not interrupted when the interval switch S
function begins after the WIWA function has elapsed.
2
immediately and current sources C and F are switched off.
2
in a discharged state. Now the capacitor is charged through the current source
2
very quickly. After the wiper operation is finished, S
Time
2
3
, to supply voltage, V
. When the after-wiping time has elapsed, the source A dis-
, to supply voltage, V
1
2
), current source F (see
in charged state is switched-off. As soon as
Batt
Batt
, the relay is activated. The internal cur-
2
causes current source A to discharge
, the water pump starts spraying the
2
2
3
is activated. The current
. Now the relay switches
is activated. The interval
Figure 2-1 on page
1
.
1
is again at ground
2
4773B–AUTO–09/05
is discharged
2)