U2043B Datasheet, PDF (3/10 Pages) TEMIC Semiconductors – Flasher, 30-mohm Shunt, Pilot Lamp to GND or V Batt

U2043B
3. Functional Description
3.1 GND (Pin 1)
The integrated circuit is protected against damage via resistor R₄ to ground (–31) in the case of
battery reversal. An integrated protection circuit together with external resistances R₂ and R₄
limits the current pulses in the IC.
3.2 Supply Voltage, V_S Power (Pin 2)
The arrangement of the supply connections to pin 2 must be so as to ensure that, on the con-
nection printed circuit board (PCB), the resistance of V_S to pin 6 is lower than that to pin 2.
3.3 Relay Control Output (Driver, Pin 3)
The relay control output is a high-side driver with a low saturation voltage and capable of driving
a typical automotive relay with a minimum coil resistance of 60Ω.
3.4 Oscillator (Pin 4 and 5)
Flashing frequency, f₁, is determined by the R₁C₁ components as follows (see Figure 1-1 on
page 1):
f₁
=
------------------¹------------------
R₁ × C₁ × 1.5
Hz
where
C₁ ≤ 47 µF
R₁ = 6.8 kΩ to 510 kΩ
In the case of a lamp outage (see pin 7) the oscillator frequency is switched to the lamp outage
frequency f₂ with f₂ ≈ 2.2 × f₁.
Duty cycle in normal flashing mode:
Duty cycle in lamp outage mode:
50%
40% (bright phase)
3.5 Supply Voltage, Sense (Pin 6)
For accurate monitoring via the shunt resistor, a minimized layer resistance from point V_S/shunt
to pin 6 is recommended.
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4720B–AUTO–09/05