Multitone RPR 563GS, Техническое руководство

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CONV.
TR101-6
VOLTAGE +4.5V
SWB+
SPEECH3V
BEC
IC105
GATE
ARRAY
D101
TR102
/SP.EN
BATTERY
PACK
DECODER BOARD
TR110
TR122
IC101
µP
TR125
B+
4
3
1
PL101
SK101
B+
GND
CHARGE
PSG10156-1
FS102
D118/
D119
D120/
D121
RPR 563GS/KGS
TM1187A Issue C Page 3 - 8
Figure 3: Decoder Board - Power Supply Distribution
DECODER BOARD
Power Supplies
30. Battery voltage (B+) is supplied from the battery pack at PL101 pin 3 and is split into
two supplies, B+ and TxB+. TxB+ powers the Radio Board transmitter power amplifier
only, via SK101 pin 13. B+ is used on both the Radio and Decoder Boards, the Radio
Board connection being at SK101 pin 7. Protection against reverse-polarity connection
is afforded by a surface-mounted fuse FS102 and diodes D118, D119.
31. The 4.5V voltage converter comprises PNP transistor TR105, T101 and associated
components as an oscillator running at between 20kHz and 100kHz. Converter output
is rectified and smoothed by D104 and C121. The output level is fed back to current
mirror control loop TR101-TR104 to bias the base of the oscillator. A constant 4.5V
is thus maintained with accuracy and temperature performance defined predominately
by the ratios of R105, R111 and R106.
32. When the Speech Enable line /SP.EN on IC101 goes low, TR122 is turned on,
supplying battery voltage (SPEECH3V) to the microphone and loudspeaker amplifier
circuits. The SPEECH3V line is also made available to the Radio Board at SK101
pin 9.
33. A `Low Battery' indication is provided by IC103. When B+ drops to 3V, the output of
IC103 applies a `low' to microprocessor IC101 at pin 44. If the line drops
below 2.2V, IC104 signals a reset to the Gate Array at pin 5.