Tait T850 II Series - Page 251

M850-00 T858/859 Circuit Operation D2.5
Copyright TEL 31/09/98
2.3 Control Circuitry
(Refer to the control section circuit diagram in Section 5.)
Figure 2.3 T858/859 Control Circuitry Block Diagram
+
Comparator
Q13 Q12
FET
Switch
+
+
+
Comparator
FET
Switch
Q11
IC1b
RV52
High Reverse Power LED
Low Forward Power LED
Reverse
Power
Meter
Reverse
Power
Alarm
Forward
Power
Meter
Forward
Power
Alarm
+7V
+7V
Tx
Key
IC1a
RV48
RV43
+
+
Q16Q15
Q10
+13.8V
Filtered
Integrator
IC1c
Control
Supply
-t°
R72
NTC
RV63
RV69
Power
Control
Shutdown
Power Level
Comparator
IC1d RV74
R58
RV57
R44
Reverse
Power
Sense
Buffer
IC3a
Buffer
IC3b
Forward
Power
Sense
Ref.
(T859 Only)
7V
Supply
13.8V
Filtered
L11
13.8V
RV69
Supply LED
IC2
IC4 IC1
Voltage
Regulator
Drive Level Clamp
(T859 Only)
Forward Power
Alarm
Reverse Power
Alarm
(RF Section -
High Temp. Sense)
Shutdown
Temperature
(T858/T878 Only)