The voltage threshold of all internal comparators has a
typical value of Vth = 10 mV.
wA voltage drop accross the shunt of Vsh Vth means no
fault in the lamp circuit and the output is disabled.
vIn the event of a voltage drop Vsh Vth, the output sup-
plies the current IO, and the pilot lamp is activated by the
vThe output is reliably disabled for a voltage at the refer-
ence pin of the comparators of VminRef 1/3 VS
The typical values of the input currents are 25 mA and are
equally large at the switch-over instant, thus making it
possible to connect protective resistors in series. The
internal threshold is independent of the value of the
protective resistor as long as all resistors of a comparator
have the same value.
It is possible to monitor the fuses of the lamp circuits by
means of an EXCLUSIVE OR function between K1 and
K3 and between K5 and K6.
If the Ref pin of K1 (orK5) is low and the Ref pin of K2
(or K6) is simultaneously high, or vice versa, a fault is
Simultaneous failure of both fuses is not detected.
A fuse is faulty if the input voltage at the pin Ref falls
below the voltage VminRef (1/3 VS).
"A fault is indicated only if it is present for td = 1.2 0.2 s.
wIf an OK pulse 100 ms occurs during this time, time
counting is reset to ”0”. An OK pulse is generated if the
comparators K1 to K8 and the input BL do not signal a
wA periodic fault signal (period of less than 1 s) is indicated
only if the mark-to-space ratio is 10/1, whereby the
pulse time corresponds to an item of fault information.
The time delay until the fault is indicated exceeds the time
td = 1.2 s in this case.
A failure in the break light circuit which is present for
longer than td is stored.
vA voltage of VBL 0.15 VS which is present at the input
BL for longer than td leads to fault indication with
storage. This allows the possibility of additional flashing
w vA voltage of VBL 0.2 VS and of VBL 0.65 VS which
is present at the input BL for longer than td leads to fault
indication without storage. It is thus possible to extend the
scope of monitoring beyond 11 lamps by means of
additional comparators ICs.
wA voltage of VBL 0.7 VS at the input BL does not cause
a fault signal.
The turn indicator and the brake light memory is
maintained by VS (terminal 15)
When VBatt (terminal 15) is applied to Pin VS, a brief
signal is produced which generates the power-on reset. As
a result, the turn indicator, the brake light memory and the
counters are reset.
A fault signal at the comparators K1 to K8 or at the
comparator Pin BL enables the output so that current IO
can flow. The output blocking voltage (VS – Vout) is
typically 1 V.
Threshold Testing without Time Delay td
To connect the input comparators directly to the output
pin, a voltage of 6 V at Pin OSC is necessary (omit ROSC
Absolute Maximum Ratings
Pulse current (2 ms)
Short circuit current (reversed battery)
Ambient temperature range
–40 to +100
4 (8) TELEFUNKEN Semiconductors
Rev. A1, 22-Oct-97