U2044B.pdf 데이터시트 (총 8 페이지) - 파일 다운로드 U2044B 데이타시트 다운로드

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Features
Temperature and Supply Voltage Compensated Flashing Frequency
Frequency Doubling Indicates Lamp Outage
Two Relay Driver Outputs with High Current-carrying Capacity and Low Saturation
Voltage
Minimum Lamp Load for Flasher Operation: ³ 1 W
Very Low Susceptibility to EMI
Protection According to ISO/TR7637/1 Level 4
Extremly Low Current Consumption < 10 µA (with Switches Open)
Reverse Polarity Protection
Three Control Inputs: Left, Right and Hazard Warning
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Description
The integrated circuit U2044B is used in relay-controlled automotive flashers. With two
output stages, each side of the vehicle is controlled separately. A left and a right direc-
tion indicator input with only a small control current makes switch contacts for small
loads possible.
The separate hazard warning input simplifies the construction of the hazard switch.
Lamp outage is indicated by frequency doubling during direction mode. Thanks to
extreme low current consumption the U2044B can be directly connected to the
battery.
Dual Output
Flasher
U2044B
Rev. 4721A–AUTO–05/03
1

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Figure 1. Block Diagram
C1
4.7 µF
14
R1
82 kW
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1
V S-6 V
9
5
+
-
K1
V S-81 mV
8
RShunt
30 mW
Contact
12
+
-
V Ref1
6
+
-
7
+
-
-
+ V Ref2
V S /2
R9
47 kW
R8
47 k W
27.5 V
-
+
11 13 GND 10
324
R2
220W
Hazard warning
R3
4.7 kW
12
R10
1.2 kW
Relay
12
R4
4.7 kW
R6
4.7 k W
right
R5
1.2 kW
R7
1.2 k W
left
30
30
30
15
31
12700
2 U2044B
4721A–AUTO–05/03

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Pin Configuration
Figure 2. Pinning DIP14/SO14
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OSC 1
14 OSC
SIL 2
13 OR2
SIR 3
12 VS
SIHW 4 U2044B 11 OR1
VS 5
10 GND
CR1 6
9 VS
CR2 7
8 LD
Pin Description
Pin Symbol
1 OSC
2 SIL
3 SIR
4 SIHW
5 VS
6 CR1
7 CR2
8 LD
9 VS
10 GND
11 OR1
12 VS
13 OR2
14 OSC
Function
Oscillator
Start input left
Start input right
Start input hazard warning
VS
Control input relay 1
Control input relay 2
Lamp failure detection
VS
IC ground
Output relay 1
VS
Output relay 2
Oscillator
U2044B
4721A–AUTO–05/03
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Functional Description
Oscillator (Pin 1 and 14) Flashing frequency, f1, is determined by the R1C1 components as follows (see Figure 1):
f1 » R-----1----´-----C---1--1----´-----1---.--5- Hz
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where C1 £ 47 µF
R1 = 6.8 kW to 180 kW
In the case of a lamp outage, the oscillator frequency is switched to the lamp outage fre-
quency f2 with f2 » 2.2 ´ f1.
Duty cycle in normal flashing mode: 50%
Duty cycle in lamp outage mode:
40% (bright phase)
Start Input Right and Left
(Pin 2 and 3)
Flashing is disabled as long as the input comparator is tied to GND (pull-down resistor
R7 or R5). The high-side flasher switch left or right changes the comparator status and
enables the output stage at pin 11 or Pin 13. R6 and R4 are protection resistors for the
input stage.
With an open flasher switch the current consumption is only I < 10 µA. The IC is kept in
stand-by mode until there is a voltage drop of V » 6.9 V at the pull-down resistor.
Direction mode can only be activated when the ignition switch is in the ON-position as
shown in Figure 1.
Start Input Hazard
Warning (Pin 4)
In contrast to the direction switches, the hazard input is a low-side type. The pull-up
resistor R10 provides the off-state. R3 is a protection resistor for the input stage. Hazard
warning can be activated independent of the ignition switch position.
Supply Voltage Sense
(Pin 5)
This pin supplies the lamp outage comparator at pin 8 and is externally connected to the
battery (Kl 30).
Control Input Relay 1
and 2 (Pin 6 and 7)
The feedback detects the bright phase and the dark phase and enables the oscillator.
Lamp Outage Detection
(Pin 8)
The lamp current is monitored via an external shunt resistor, RShunt and an internal com-
parator, K1, with its reference voltage of typically 81 mV (VS = 12 V). The outage of one
lamp out of two lamps is detected according to the following calculation:
Nominal current of 1 lamp: 21 W/(VS = 12 V):
Nominal current of 2 lamps: 2 ´ 21 W / (VS = 12 V):
Ilamp = 1.75 A
Ilamp = 3.5 A
We recommend setting the detection threshhold in the middle of the current range:
Ioutage » 2.7 A
Thus the shunt resistor is calculated as:
RShunt = VT (K1)/Ioutage
RShunt = 81 mV/2.7 A = 30 mW
Comparator K1's reference voltage is matched to the characteristics of filament lamps
(see section “Control Signal Threshold”).
4 U2044B
4721A–AUTO–05/03

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U2044B
Supply Voltage (Pin 9)
GND (Pin 10)
Control Output Relay 1
and 2 (Pin 11 and 13)
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Supply Voltage Power
(Pin 12)
The combination of the shunt resistor and the resistance of the wire harness prevents
pin 8 from a too high voltage in the case of shorted lamps.
This pin supplies the oscillator, the comparators and the logic parts of the IC.
The integrated circuit is protected against transients according to ISO-TR 7637-3 level 3
via resistor R2 to ground (-31). An integrated protection circuit together with external
resistors R2, R3, R4, R6, R8 and R9 limits the current pulses in the IC. The IC is also pro-
tected against reversed battery.
The relay control outputs are high-side drivers with a low saturation voltage and capable
of driving a typical automotive relay with a coil resistance of 60 W.
This pin supplies the relay drivers connected directly to the battery (Kl 30). It is internally
clamped by a 27-V Z-diode.
Absolute Maximum Ratings
Reference point pin 1
Parameters
Supply voltage, 1 min, pins 5, 9 and 12
Junction temperature
Ambient temperature range
Storage temperature range
Symbol
VS
Tj
Tamb
Tstg
Value
24
150
-40 to +100
-55 to +150
Unit
V
°C
°C
°C
Thermal Resistance
Parameters
Junction ambient, DIP14
Junction ambient, SO14
Symbol
RthJA
RthJA
Value
90
120
Unit
K/W
K/W
Electrical Characteristics
Typical values under normal operation in application circuit Figure 1, VS (+30) = 12 V.
Reference point ground (-31), Tamb = 25°C, unless otherwise specified
Parameters
Test Conditions
Symbol
Supply voltage range
Supply current, switches open
Output current for relay driver
Saturation voltage
Relay output reverse current
Relay coil resistance
Start delay
Pins 5, 9, 12
Pins 5, 9, 12
Pins 11, 13
RL = 82 W
VS = 8 V
VS = 12 V
Pin 11, 13
First bright phase
VS
IS
IO
VO
IO
RL
ton
Min.
8
60
Typ.
Max.
18
10
300
1.0
1.2
0.1
10
Unit
V
µA
mA
V
V
mA
W
ms
4721A–AUTO–05/03
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