Interval and Wipe/Wash Wiper Control IC with Delay U641B

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1 Features Interval Pause: to 0 s After-wiping Time: to 0 s Wiper Motor's Park Switch 0. s Prewash Delay Wipe/Wash Mode Priority One External Capacitor Determines All Time Sequences Relay Driver with Z-diode Interference Protection According to DE 0839 or ISO/TR 737/1 Load-dump Protected Description The U1B is a bi-polar integrated circuit designed for the wiper application in the automotive market. It includes wipe, wash and internal mode. Functional Description As a convenience feature of the windshield wiper, intermittent and wipe/wash operation functions are implemented in most of the automobiles. The U1B is a costeffective solution for an accurate timing function control. Wipe/wash mode has priority over interval mode. Interval pause and after-wiping 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 the U1B. Interval and Wipe/Wash Wiper Control IC with Delay U1B Figure 1. Block Diagram S OUT PARK WASH Ref Ref Load-dump comparator Park switch comparator Input comparator Ref Ref Logic Wipe/wash comparator Interval comparator A B C D E F 1 3 GND INT C t R t Rev.

2 Pin Configuration Figure. Pinning GND 1 8 S INT 7 OUT CT 3 U1B PARK RT 5 WASH Pin Description Pin Symbol Function 1 GND Ground INT Interval switch 3 CT Timing capacitor C RT After-wiping time resistance 5 WASH Wipe/wash switch PARK Park switch for wiper motor 7 OUT Relay control output 8 S Supply voltage terminal 15 U1B

3 U1B Circuit Description Interval Function, Pin Wipe/Wash (WIWA) Operation, Pin 5 Interval and WIWA Functions By closing the interval switch, S, to supply voltage, Batt, the relay is activated. The internal current source (pin 3) which holds the capacitor C in charged state is switchedoff. As soon as there is a positive potential at the park switch (S 1 ), current source F (see Figure 1 on page 1) charges the capacitor C very quickly. After the wiper operation is finished, S 1 is again at ground potential, the relay is in the off position - interval pause begins - the capacitor C is discharged through the current source C, till the voltage at pin 3 is below the threshold of. Interval pause can be adjusted between s to 0 s with the help of potentiometer R 3. Now the relay switches on and the next interval cycle begins. Opening switch S causes current source A to discharge C immediately and current sources C and F are switched off. By closing the WIWA switch, S 3, to supply voltage, Batt, the water pump starts spraying the water on the windshield. During this function, the current source A is switched-off which keeps the capacitor C in a discharged state. Now the capacitor is charged through the current source F. If (after a time interval of approximately 00 ms) the voltage at the capacitor is greater than.1, 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.. 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 Time. When the after-wiping time has elapsed, the source A discharges the capacitor. The relay switch is independent of the park switch S 1. The interval function is interrupted immediately when the switch S is activated. The current source A discharges the capacitor to a value of, 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. The Wipe/Wash function is not interrupted when the interval switch S is activated. The interval function begins after the WIWA function has elapsed. 3

4 Figure 3. Application Circuit with Interval and Wipe/Wash Operation 10 kω R R 5 10 kω Relay µf 10 C 1 U1B 1.7 kω 3 µf R C R R Ω = 130 KΩ R 3 S 1 S 10 kω Park switch M WIWA M S 3 Wiper motor Interval switch Water pump U1B

5 U1B Absolute Maximum Ratings Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Parameters Pin Symbol alue Unit Supply voltage t = 0 s, terminal 15 8 Batt 8 Supply current t = ms t = 00 ms Relay control output current (DC) t = 00 ms Pulse Current (Control Inputs) t = 00 ms Park switch, S 1 Wipe/Wash switch, S 3 Interval switch, S 8 I 8 I I 7 00 I 7 1. I I 5 I Power dissipation T amb = 90 C P tot 500 mw Storage temperature range T stg -55 to +15 C Ambient temperature range T amb -0 to +85 C A ma ma A ma Thermal Resistance Parameters Symbol alue Unit Junction ambient DIP8 R thja 10 K/W SO8 R thja 10 K/W 5

6 Electrical Characteristics Batt = 1, T amb = 5 C, reference point is pin 8 (see Figure 3 on page ) unless otherwise specified. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Supply voltage Batt Supply current 8 I 8 10 ma Z-diode limitation 1 7. Overvoltage Threshold current I1-50 ma Threshold voltage Batt 35 Relay Control Output 7 Saturation voltage I 7 = 100 ma I 7 = 00 ma Leakage current I µa Park Switch Internal pull-up resistance R = 10 k R 50 k Switching threshold voltage -3.3 I Protection diode = -10 ma I = 10 ma Input C t Internal resistance R Interval Input R =.7 to 30 k Protection diode I = -10 ma I = 30 ma/10 ms WASH Input R 5 = 10 k 5 Switching threshold/ Hysteresis Protection diode I 5 = -10 ma I 5 = 10 ma Switching Characteristics R = 7 k to 300 k, I = -150 µa Interval time R 3 = 0 k R 3 = 10 k / -5. t Prewash delay t del 00 ms After-wipe-time R = 130 k 5 t s s U1B

7 U1B Diagrams Figure. Interval Pause = f (T); C t = µf Interval Pause (s) R int = 0 R int = 5 kω R int = 10 kω Temperature ( C) Figure 5. After-wiping Time = f (T); C t = µf; Batt = 8 1 After-wiping Time (s) 10 8 Batt = 8 = 51 kω = 130 kω = 300 kω Temperature ( C) Figure. Prewash Time = f (T); C t = µf 1.0 Prewash Delay (s) Batt = 1 Batt = Temperature ( C) 7

8 Figure 7. Interval Pause = f (R INT ); C t = µf 1 Interval Pause (s) Interval Resistor (kω) Figure 8. After-wiping Time = f (T); C t = µf; Batt = 1 1 After-wiping Time (s) 10 8 Batt = 1 = 51 kω = 130 kω = 300 kω Temperature ( C) 8 U1B

9 U1B Ordering Information Extended Type Number Package Remarks U1B DIP8 U1B-FP SO8 Package Information Package DIP8 Dimensions in mm max min 3.3. max 0.3 max technical drawings according to DIN specifications 1 Package SO8 Dimensions in mm technical drawings according to DIN specifications 1 9

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Interval and Wipe/Wash Wiper Control IC with Delay U641B

Interval and Wipe/Wash Wiper Control IC with Delay U641B Features Interval Pause: s to 0s After-wiping Time: s to 0s Wiper Motor s Park Switch 0.s Prewash Delay Wipe/Wash Mode Priority One External Capacitor Determines All Time Sequences Relay Driver with Z-diode