Technical data

2 CIRCUIT DESCRIPTION RT2047 DSC - PART II
2.6 INTERFACE UNIT MODULE 6/600
2.6.1 ON/OFF FUNCTION
ON
When the ON/OFF push button is activated Q4-6 is turned on and the relay RE3-6 is engaged. When the
µC leaves reset condition PC5 is set to high level and Q5-6 will be conducting, keeping Q4-6 on.
OFF
When the ON/OFF push button is activated again U19-6 receives a message on the serial interface. Then
it stores the actual settings of the channel, volume, squelch, power level, INT/USA mode and scan time.
Afterwards PC5 is turned low, and Q5-6, Q4-6, and RE3-6 will switch off.
2.6.2 BATTERY SENSOR
If the battery voltage drops below approx. 9.5V the output of U7/3-6 goes high, and the µC will switch off
the set.
2.6.3 DELAYED OFF
If the ON/OFF push button is kept activated longer than approx. 3 seconds, pin 12 on U12/2-6 will go low
forcing the µC into reset. This means that as soon as the button is released the set will switch off.
2.6.4 TEMPERATURE SENSOR
Not mounted.
2.6.5 5V SUPPLY
The 5V power supply is an integrated, non adjustable regulator.
2.6.6 10V SUPPLY
The 10V supply is a serial regulator with current limiter. When it is switched on Q10-6 gets base current
through R32-6 and R41-6. Thus Q10-6 draws collector current so that Q9-6 turns on and the output
voltage rises. When Q13-6 begins to conduct the current in Q10-6 is reduced. Thus the base current in
Q9-6 is also reduced and the output voltage stabilises . The current limiting starts when the voltage across
R40-6 is big enough to turn Q6-6 on and makes the current flow through D8-6 to the emitter of Q10-6,
and therefore the current in Q10-6 and also in Q9-6 will decrease which results in a decrease of the output
voltage.
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