Dräger 8000 IC Function Description page 41

3.2.7.2 Detailed description of function blocks
a. Supply voltage +15 V
b. Supply voltage -15 V
c. Supply voltage +5 V
d. Power-fail recognition
e. Driving of beeper
f. Storage battery charging connection
a. Supply voltage +15 V
The AC-voltage at pins 1 a/c and 2 a/c is rectified, filtered and routed to the +15 V fixed
voltage regulator.
b. Supply voltage -15 V
The AC-voltage at pins 3 a/c and 4 a/c is rectified, filtered and routed to the -15 V fixed voltage
regulator.
c. Supply voltage +5 V
The AC voltage at pins 5/6 a/c and 7/S a/c is rectified, filtered and routed to the 5 V fixed
voltage regulator which is attached outside.
d. Power-fail recognition
The AC-voltage at pins 1 a/c and 2 a/c is processed for triggering of mono flop D1. If a half-
wave fails or when the device is switched off an NM1 is released by the output of the mono.
Via pin 28 a/c the position of the mains switch at the time of the power fail is evaluated and
thus a flag is generated for cold-/warmstart decision for the software after the mains voltage
has returned.
e. triggering of beeper
During operation the beeper is driven via pin 24 a/c. The beeper is active when the H-level is
present at this pin. Capacitor C12 and diodes V33 and V34 prevent a short response of the
beeper when the device is switched off. In case of power fail the beeper is fed by the storage
battery via the closed mains switch auxiliary contacts. Via pin 23 a/c an external LED is
switched on.
6141.22X Incubator 8000 IC/SC/NC
Function Description
09.99 Page 41 of 49