U644B
Flasher, 18-mW Shunt, Extremly Low Current Consumption
Description
The bipolar integrated circuit, U644B, is used ...
U644B
Flasher, 18-mW Shunt, Extremly Low Current Consumption
Description
The bipolar integrated circuit, U644B, is used in relaycontrolled automotive flashers where a high level EMC is required. Lamp outage is indicated by frequency doubling during hazard warning as well as direction mode. If the flasher module provides an 4-pin connector the control pin of U644B (Pin 6) can be used to operate the IC in an extremly low-current mode.
Features
D Frequency doubling indicates lamp outage D Frequency independent of temperature and
voltage
change
D Minimum lamp load for flasher operation: D Very low susceptibility to EMI
1 W
D Relay driver output with high current-carrying
capacity and low saturation
voltage
D Protection according to ISO TR7637/1 level 4 D Control input (Kl 15)
Ordering Information
Extended Type Number U644B U644B-FP Package DIP8 SO8 Remarks
Block Diagram
R5 10 kW 30 2 Measuring comparator K 1 V S – 49 mV 4 K1 6 15
C1
R4 Shunt 20 kW 20 kW 7 2 kW 3
18 mW
K2 R1 Pulse generator 49 a Comparator K 2
20 kW 8
Relay R3 3.3 kW 30 V 1 GND R2 220 W GND –31 49 a
5
K3 49 a Comparator K 3 20 kW
13 kW
12707
Figure 1. Application circuit as a car flasher with control input Resistor R1, R2 and R3: 1/4 Watt R2 for protection against continuous reversed polarity: 1 Watt
TELEFUNKEN Semiconductors Rev. A2, 25-Feb-97
1 (6)
U644B
+V S +49 2 Measuring comparator K 1 V S – 49 mV 4 K1 6
C1
R4 Shunt 20 kW 20 k 7 2 kW 3
18 mW
K2 R1 Pulse generator 49 a Comparator K 2...