ATMEL U2640B

U2640B
Intemittent- and Wipe/ Wash Control for Wiper Systems
Description
With the U264xB, Atmel Wireless & Microcontrollers
developed a family of intermittent- and wipe/wash control circuits for windshield or backlite wiper systems with
identical basic functions. The circuit design provides the
possibility to generate ”x” versions using different metallization masks. Thus, it is easy to verify a broad range of
time sequences which can be set independently of each
other.
Features
Relay activation can be controlled by a limit switch of
the wiper motor or by a fixed activation period for
systems without limit switch
Relay activation:
0.48 s
Interval pause:
5.8 s
Debounced input stages
After wiping:
5.2 s
Enable/disable of pre-wash delay by program pin
Pre-wash delay:
0.52 s
Polarity of WIWA: VBatt
Wipe/wash mode with priority
Polarity of INT:
Protected in accordance to ISO/TR 7637–1
VBatt
Relay output is protected with a clamping diode
EMC with intergrated filters
Block Diagram
VS
OSC
Voltage
stabilization
and
POR
Oscillator
INT
21 V
WIWA
21 V
LS
Input
comparator
Logic
21 V
Loaddump
detection
and
output
control
Open-collector
relay driver
REL
21 V
PP
21 V
13944
GND
Figure 1. Block diagram
Ordering Information
Extended Type Number
Package
U2640B
DIP8
U2640B–FP
SO8
Rev. A4, 03-Apr-01
Remarks
1 (10)
U2640B
Pin Configuration
Pin
Symbol
Function
1
INT
2
WIWA
3
LS
Limit switch (wiper motor) input
4
PP
Program pin
5
GND
Ground
6
REL
Relay output
7
VS
8
OSC
Intermittent input
Wipe/wash (WIWA) input
Supply voltage
INT
1
8
OSC
WIWA
2
7
VS
LS
3
6
REL
PP
4
5
GND
13365
RC oscillator input
Figure 2. Pinning
Functional Description
All times specified below refer to an oscillator frequency
of 200 Hz. Figures 9 to 16 show the dependencies of the
times upon battery voltage and temperature. The
temperature dependence of the oscillator frequency is
essentially determined by the temperature coefficient of
the oscillator capacitor. The temperature dependence of
the oscillator frequency can be reduced to minimum with
a slightly negative temperature coefficient (N100). The
capacitor used in figures 10 and 11 has a slightly positive
temperatur coefficient.
All times are permanently set and can be changed only
jointly within certain limits by adjusting the oscillator
frequency. See table 1.
Intermittent Function
The relay is energized for the time tON after the switch
INT is switched on with respect to VBatt and after expiration of time tD (debounce).
Interval Pause
The interval pause tINT = 5.8 s follows tON. Opening of
switch INT causes a debounce time, tD, and reclosing
results in the relay on-time, tON, after tD.
Wipe/Wash Function without Pre-Wash
Delay (PP connected to GND)
The water pump is switched on when the switch WIWA
is pressed and, after the debounce time, tD, the relay is
energized. After-wiping time tAW = 5.2 s starts as soon as
switch WIWA is opened and the debounce time, tD, has
expired. If the limit switch is connected, the relay remains
energized until the wiper arm returns to park position, i.e.,
the motor current flows via the relay contact only.
Wipe/Wash Function with Pre-Wash Delay
(PP connected to VS)
The debounce time ranges between 60 ms and 80 ms. A
time period of 5 ms to 40 ms for internal sequence control
must be added (asynchronism between operating instant
and internal clock) e.g., the response time may range from
65 ms up to 120 ms.
In wipe/wash mode, the relay is energized after a delay
time. The water pump can spray water onto the windscreen during the delay time, tDEL.
If the limit switch of the windscreen wiper motor is
connected to Pin LS, the relay is energized as long as the
switch is at high potential, regardless of the relay on-time,
tON, i.e., the motor current in interval mode flows via the
relay contact only. In park position, the motor winding at
both ends is connected to ground via the limit switch and
the motor is decelerated immediately. The limit switch
input is debounced with tDL = 17 ms.
tDEL = tD + 0.44 s = 0.52 s
The relay on-time, tON, always elapses – even if the
interval switch was opened beforehand.
2 (10)
The on-delay time of the U2640B is:
If switch WIWA is closed longer than tD but shorter than
tDEL, the after-wiping time, tAW, starts after expiration of
tDEL. The wipe/wash function with or without on-delay
tDEL can be selected by programming PP.
PP connected to GND:
PP connected to VS:
without pre-wash delay
with pre-wash delay
The after-wiping time, tAW, is re-triggerable in both cases.
Rev. A4, 03-Apr-01
U2640B
Intermittent and Wipe/Wash Mode
Power Supply
The wipe/wash function has priority over the interval
function. If switch WIWA is closed during the interval
function, wipe/wash mode is activated immediately after
the debounce time, tD, even if an on-delay is programmed
(tDEL = 0 s). Expiry of tAW is directly followed by the next
relay on-time, tON, of intermittent mode.
For reasons related to protection against interference and
destruction, the Pin VS must be provided with an RC network for limiting the current in the event of overvoltage
and for buffering in the event of voltage drops.
Proposed ratings: RV = 510 , CV = 47 F. An integrated
14-V Zener diode is connected between VS and GND.
Oscillator
Interference Voltages and Load-Dump
All timing sequences are derived from an RC-oscillator
whose charging time, t1, is determined by an external
resistor, ROSC, and whose discharging time, t2, is
determinated by an integrated 2-k resistor. Since
tolerance and temperature response of the integrated
resistor are far higher than those of the external resistor,
t1/t2 must be selected to be greater than 20 for stability
reasons. The minimum value of ROSC should not be less
than 68 k.
In the case of transients, the integrated Zener diode limits
the voltage of the relay output to approximately 28 V. In
the case of load-dump, a current (dependent upon RV and
CV) flows through the integrated 14-V Zener diode, and
the relay output is switched on at VBatt > 30 V in order to
avoid destruction of the output. The output transistor is
rated such that it can withstand the current generated during the load-dump through the relay coil. In practice, the
windscreen wiper motor is switched on via the relay and
thus the amplitude of the load-dump pulse is limited. The
supply voltage of the circuit is limited to 14 V by the integrated Zener diode, and the inputs are protected by
external protective resistors and integrated Zener diodes.
Calculating cycle duration and frequency:
and
t = t1 + t2 = COSC ( 0.74 ROSC + 2260 )
fOSC = 1/t
Calculating the capacitor for a given resistor:
COSC = t / ( 0.74 ROSC + 2260 )
RF suppression is implemented with a low-pass filter at
the inputs, consisting of a protective resistor and the integrated capacitor.
Calculating the oscillator resistance for a given capacitor:
ROSC = 1.34 ( t / COSC – 2260 )
Power-on Reset (POR)
Recommended frequency: fOSC = 200 Hz
(for ROSC = 200 k, COSC = 33 nF)
When the supply voltage is applied, a power-on reset
pulse is generated which sets the circuit’s logic to a
defined initial state. The POR threshold is approximately
VS = 4.3 V.
All times can be varied jointly within specific limits by
varying the oscillator frequency (see table 1). The oscillator is operable up to 50 Hz.
Table 1 Change in times by varying the oscillator frquency
fosc (Hz)
tD [ms]
tDL [ms]
tON [ms]
tINT [s]
tAW [s]
tDEL [s]
100
140
35
960
11.84
10.24
920
120
116
29
800
9.68
8.53
766
140
100
25
686
8.45
7.31
657
160
87
22
600
7.40
6.40
575
180
77
19
533
6.57
5.68
511
200
70
17
480
5.92
5.12
460
220
64
16
436
5.38
4.65
418
240
58
14
400
4.93
4.26
383
260
54
13
370
4.55
3.94
353
280
50
12
343
4.23
3.66
328
300
46
11
320
3.95
3.41
306
400
35
9
240
2.96
2.56
230
Rev. A4, 03-Apr-01
3 (10)
U2640B
Absolute Maximum Ratings
With recommended external circuitry
Parameter
Test Conditions
Supply voltage (static)
5 min
Symbol
VBatt
Value
24
Unit
V
Supply current pulse
2 ms
IS
1.5
A
Supply current pulse
300 ms
IS
150
mA
IREL
300
mA
IREL
1.5
A
Ambient temperature range
Tamb
–40 to +95
°C
Storage temperature range
Tstg
–55 to +125
°C
Relay output current (static)
Relay output current pulse
300 ms
Power dissipation
DIP8
Ptot
0.45
W
Power dissipation
SO8
Ptot
0.34
W
Symbol
RthJA
RthJA
Value
120
160
Unit
K/W
K/W
Thermal Resistance
Parameters
Junction ambient
Junction ambient
DIP8
SO8
Electrical Characteristics
Reference point Ground GND, Tamb = 25C, VBatt = 13.5 V, unless otherwise specified (see figures 11 and 12)
Parameters
Voltage supply
Supply voltage
Supply current
Undervoltage threshold
(POR)
Internal Z-diode
Internal capacitor
Series resistance
Filter capacitor
Oscillator input OSC
Internal discharge resistor
Lower switching-point
voltage
Upper switching-point
voltage
Input current
Oscillator frequency
Test Conditions / Pin
Pin 7
Symbol
Min
VBatt
IS
VS
6.0
0.5
3.0
VZ
CS
RV
CV
13.5
Typ
Max
Unit
2.0
16.0
3.0
5.1
V
mA
V
16.2
V
pF
F
14.0
15
510
47
Pin 8
VOSC = 0 V
RDIS
VOSC
1.3
2.0
3.2
0.16VS 0.20VS 0.24VS
k
V
VOSC
0.55VS 0.60VS 0.65VS
V
–IOSC
fOSC
1
200
2
50 k
A
Hz
Note: All internally generated time sequences are derived from the oscillator frquency. The tolerances refer to a
frequency adjusted to fOSC = 200 Hz.
4 (10)
Rev. A4, 03-Apr-01
U2640B
Electrical Characteristics (continued)
Reference point Ground GND, Tamb = 25C, VBatt = 13.5 V, unless otherwise specified (see figures 11 and 12)
Parameters
Test Conditions / Pin
Symbol
Input limit switch LS
Pin 3
Internal protection-diode
ILS = 10 mA
VLS
voltage
Internal capacitor
CLS
Switching threshold
VLS
voltage
Input current
VLS = VS
ILS
Internal pull-up resistor
RLS
External protection resistor
RS
Inputs INT, WIWA and PP
Pins 1, 2 and 4
Internal protection-diode
IE = 10 mA
VE
voltage
Internal capacitor
CE
Switching threshold
VE
voltage
Input current
VE = 0 V
–IE
Internal pull-down resistor
RE
External protection resistor
RS
Relay output
Pin 6
Saturation voltage
I = 100 mA
VREL
Saturation voltage
I = 200 mA
VREL
Z-diode clamp voltage
I = 10 mA
VREL
Leakage current
V = 14 V
IREL
Relay coil resistance
RREL
Load-dump protection
VBatt
threshold
Internal pulse times
Debouncing period inputs INT/WIWA 12 - 16 clocks
tD
Debouncing period inputs LS
3 – 4 clocks
tDL
Relay activation time
96 clocks
tON
Intermittent pause
tINT
After wiping period
1024 68 clocks
tWIWA
Pre-wash delay, reaction
88 – 96 clocks
tDEL
time for switch-on delay =
tDEL + tD
Min
Typ
Max
Unit
19.5
21.0
25.5
V
0.375VS
0.5VS
0.675VS
pF
V
13
10
20
1
27
A
k
k
19.5
21.0
25.5
V
pF
V
25
25
0.375VS
0.5VS
0.675VS
13
10
20
1
27
A
k
k
1.1
1.5
25.5
12
V
V
V
A
V
19.5
21.0
60
28
33
42
70
17.5
480
5.92
80
20
60
15
4.78
440
5.46
480
ms
ms
ms
s
s
ms
Note: All internally generated time sequences are derived from the oscillator frquency. The tolerances refer to a
frequency adjusted to fOSC = 200 Hz.
Rev. A4, 03-Apr-01
5 (10)
1.0
1.0
0.9
0.9
0.8
0.8
0.7
0.7
t DEL( s )
t ON ( s )
U2640B
0.6
0.5
0.4
0.6
0.4
0.3
0.3
0.2
0.2
0.1
0.1
0.0
max
0.5
min
0.0
6
8
10
12
14
16
18
6
8
10
VBatt (V)
14
16
18
Figure 5. Pre-wash delay = f (VBatt)
10
10
9
9
8
8
7
7
t AW ( s )
t INT ( s )
Figure 3. Relay activation = f (VBatt)
6
5
4
max
6
5
min
4
3
3
2
2
1
1
0
0
6
8
10
12
14
16
VBatt (V)
Figure 4. Interval pause = f (VBatt)
6 (10)
12
VBatt (V)
18
6
8
10
12
14
16
18
VBatt (V)
Figure 6. After-wipe time = f (VBatt)
Rev. A4, 03-Apr-01
U2640B
0.8
8
7
0.7
max
6
t AW ( s )
t ON ( s )
0.6
0.5
5
min
4
3
0.4
2
0.3
0.2
–40
1
–20
0
20
40
60
Temperature (°C )
80
0
–40
100
0
20
40
60
80
100
Temperature (°C )
Figure 7. Relay activation = f (Temperature)
Figure 9. After-wipe time = f (Temperature)
0.8
8
7
0.7
6
0.5
min
t INT ( s )
max
0.6
t DEL( s )
–20
5
4
3
0.4
2
0.3
0.2
–40
1
–20
0
20
40
60
Temperature (°C )
80
100
Figure 8. Pre-wash delay = f (Temperature)
0
–40
–20
0
20
40
60
80
100
Temperature (°C )
Figure 10. Interval pause = f (Temperature)
Note: The temperature characteristic is caused by the temperature coefficient TC of the external capacitor
Rev. A4, 03-Apr-01
7 (10)
U2640B
Application Examples
Kl 15
Rv
510 Ω
Rosc
200 kΩ
CV
Cosc
47 µF
33 nF
8
6
7
5
U2640B
1
2
Rs
10 kΩ
INT
WIWA
3
4
Rs
10 kΩ
Water–
M
pump
M
Wiper–
motor
13903
Figure 11. Application without limit switch
Kl 15
Rv
510 Ω
Rosc
200 kΩ
CV
Cosc
47 µF
33 nF
8
6
7
5
U2640B
1
2
3
Rs
10 kΩ
INT
4
Rs
10 kΩ
Rs
10 kΩ
WIWA
Water–
M
pump
Wiper–
M
motor
End–
switch
13904
Figure 12. Application with limit switch
8 (10)
Rev. A4, 03-Apr-01
U2640B
Package Information
Package DIP8
Dimensions in mm
9.8
9.5
1.64
1.44
7.77
7.47
4.8 max
6.4 max
0.5 min
0.58
0.48
3.3
0.36 max
9.8
8.2
2.54
7.62
8
5
technical drawings
according to DIN
specifications
13021
1
4
Package SO8
Dimensions in mm
5.2
4.8
5.00
4.85
3.7
1.4
0.25
0.10
0.4
1.27
6.15
5.85
3.81
8
0.2
3.8
5
technical drawings
according to DIN
specifications
13034
1
Rev. A4, 03-Apr-01
4
9 (10)
U2640B
Ozone Depleting Substances Policy Statement
It is the policy of Atmel Germany GmbH to
1. Meet all present and future national and international statutory requirements.
2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems
with respect to their impact on the health and safety of our employees and the public, as well as their impact on
the environment.
It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as
ozone depleting substances (ODSs).
The Montreal Protocol (1987) and its London Amendments (1990) intend to severely restrict the use of ODSs and forbid
their use within the next ten years. Various national and international initiatives are pressing for an earlier ban on these
substances.
Atmel Germany GmbH has been able to use its policy of continuous improvements to eliminate the use of ODSs listed
in the following documents.
1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively
2. Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental
Protection Agency (EPA) in the USA
3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C (transitional substances) respectively.
Atmel Germany GmbH can certify that our semiconductors are not manufactured with ozone depleting substances
and do not contain such substances.
We reserve the right to make changes to improve technical design and may do so without further notice.
Parameters can vary in different applications. All operating parameters must be validated for each customer
application by the customer. Should the buyer use Atmel Wireless & Microcontrollers products for any unintended
or unauthorized application, the buyer shall indemnify Atmel Wireless & Microcontrollers against all claims,
costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal damage, injury or death
associated with such unintended or unauthorized use.
Data sheets can also be retrieved from the Internet:
http://www.atmel–wm.com
Atmel Germany GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany
Telephone: 49 (0)7131 67 2594, Fax number: 49 (0)7131 67 2423
10 (10)
Rev. A4, 03-Apr-01