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參數(shù)資料
| 型號(hào)： | U644B |
| 英文描述： | Flasher, 18-m Shunt, Extremly Low Current Consumption |
| 中文描述： | 閃光器，18米分流，Extremly低電流消耗 |
| 文件頁(yè)數(shù)： | 3/6頁(yè) |
| 文件大小： | 202K |
| 代理商： | U644B |
U644B
TELEFUNKEN Semiconductors
Rev. A2, 25-Feb-97
3 (6)
Functional Description
Pin 1
, GND
The integrated circuit is protected against damage via
resistor R
2
to ground (–31) in the case of battery reversal.
An integrated protection circuit and the external
resistances R
1
and R
2
limit the ac-current pulse in the IC.
Pin 2
, Supply voltage, V
S
- Power
Connected directly to battery (Kl 30).
Pin 3
, Relay control output (driver)
The relay control output is a high-side driver with a low
saturation voltage and capable to drive a typical automo-
tive relay with a minimum coil resistance of 60 .
An integrated overvoltage detection disables the output at
V
S
20 V to protect the lamps during jump start
Pin 4 and 5
Oscillator
Flashing frequency, f
1
, is determined by the R
1
C
1
components as follows (see figure 1):
1
R
1
C
1
where
C
1
R
1
6.8 k to 510 k
f
1
1.5Hz
47 F
In the case of a lamp outage (see Pin 7) the oscillator
frequency is switched to the lamp outage frequency f
2
with f
2
2.2 f
1
.
Duty cycle in normal flashing mode: 50%
Duty cycle in lamp outage mode: 40% (bright phase)
Pin 6
, Supply voltage, control input
When the IC is powered by the battery Pin 6 is the control
input to switch the IC to zero current consumption during
stand-by.
Pin 7
, Lamp outage detection
The lamp current is monitored via an external shunt
resistor R
4
and an internal comparator K1 with its
reference voltage of typ. 49 mV (V
S
=
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 / (V
S
= 12 V):
I
lamp
=
1.75 A
Nominal current of 2 lamps: 2 x 21 W / (V
S
= 12 V):
I
lamp
= 3.5 A.
The detection threshold is recommended to be set in the
middle of the current range: I
outage
Thus the shunt resistor is calculated as:
R
sh
= V
T
(K1) / I
outage
R
sh
=
49 mV/2.7 A = 18 m .
Comparator K1‘s reference voltage is matched to the
characteristics of filament lamps (see “control signal
threshold” in the data part).
The combination of shunt resistor and resistance of wire
harness prevents Pin 7 from a too high voltage in the case
of shortet lamps.
2.7 A
Pin 8
, Start input
Start condition for flashing: the voltage at Pin 8 has to be
below K3 threshold (flasher switch closed).
Humidity and dirt may decrease the resistance between
49 a and GND. If this leakage resistance is
is still kept in its off-condition. In this case the voltage at
Pin 8 is between the thresholds of comparators K2 and
K3.
During the bright phase the voltage at pin 8 is above the
K2
threshold, during the dark phase it is below the K3
threshold.
For proper start conditions a minimum lamp wattage of
1 W is required.
5 k the IC
Absolute Maximum Ratings
Reference point Pin 1
Parameters
Symbol
V
S
I
FSM
I
FSM
I
FSM
I
O
P
tot
P
tot
P
tot
P
tot
Value
18
1.5
1.0
50
0.3
230
300
690
560
Unit
V
A
A
mA
A
mW
mW
mW
mW
Supply voltage
Surge forward current
Pin 2
Pin 2
Pin 2
Pin 8
Pin 3
DIP8
SO8
DIP8
SO8
t
P
= 0.1 ms
t
P
= 300 ms
t
P
= 300 ms
Output current
Power dissipation
T
amb
= 120
°
C
T
amb
= 105
°
C
T
amb
=
60
°
C
T
amb
=
60
°
C
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相關(guān)代理商/技術(shù)參數(shù) |
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| U644B-FP | 制造商:TEMIC 制造商全稱:TEMIC Semiconductors 功能描述:Flasher, 18-m Shunt, Extremly Low Current Consumption |
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