U6432B-FP

The U6432B-FP has the following features including Temperature and voltage compensated frequency;Warning indication of lamp failure by means of frequency doubling only in direction mode;Voltage dependence of the car indicatar lamps also compensated for lamp failure;Relay output with high current carrying capacity and low saturation voltage;Load-dump protection.

Based on TEMIC's expertise in automotive flashers in bipolar technology, the U6432B is an improvement of the well known U6043B.The detection point for lamp failure can be calculated from the control signal threshold, typically 49 mV with Vs=12 V With a measuring resistance of R3=18 m,the frequency changeover is reached at a lamp load of 21 W +11.4 W. The variation of the control signal threshold  supply  voltage  takes into  account  the  PTC characteristic of filament lamps.A voltage drop at the shunt resistor R3 between 49 mV and 15mV let the flasher work in frequency doubling mode.If the voltage drop falls of V3MAx=15mV the frequency doubling is disabled.U6432B-FP can be achieved either with a switch which by-passes the shunt resistor (e.g. a special hazard warning switch) or with a small lamp load.The arrangement of the supply connections to Pin 2 and 6 must ensure that, on the connection PCB,the layer resistance from VS to Pin 6 is lower than the one to Pin 2.

Frotection in the case of battery reversal: The resistors R1,R2 and the relay coil limit the currents and the integrated circuit would not be damaged. To achieve a protection for continuous battery reversal, resistor Rt U6432B-FP should be capable of 30 mA (0.5 W type).A shot circuit between indicator lamp (49a) and ground (31) can give rise to a voltage drop of about 4 V across the measuring resistance R3.In this case, the integrated circuit would not be damaged.The resistors U6432B-FP Rl and R2are needed to protect the circuit against possible damage. An integrated protection circuit,together with these external resistors, limits the impulse current in the integrated circuit.