Kenwood TK-6110 Service Manual page 16

TK-6110
6. Power Supply Circuit
The power (+B), which is suplied via a power connector,
is routed to the TX drive amplifier (Q4 and Q5), the TX final
amplifier (Q6 and Q7), and the audio power amplifier
(IC102).
The power switch (Q110) converts the power (+B) to SB.
The 8V REG (IC103) converts SB to 8C.
The two, 5V REGs (IC104 and IC602) converts 8C to 5C
and 5CM respectively. The 5CM is the power supplied to
the CPU. 8C is distributed between the TX circuit power (8T
and 8TB) and the RX circuit power (8R).
+B
Q110
SW
Power
control
circuit
Fig. 8 Power supply circuit
7. Control Circuit
The control unit circuit consists of microprocessor IC604
and flash memory IC607. It controls the TX-RX unit and
transfers data to and from the Display unit. The CPU (IC604)
mainly performs the following :
1) Switching between transmission and reception by PTT
signal input.
2) Reading channel, frequency, and program data from the
memory circuit.
3) Sending frequency program data to the PLL.
4) Controlling squelch on/off from the squelch circuit.
5) Controlling the audio mute circuit by decode data input.
6) Transmitting encode data (QT, DQT).
7) Sending serial data to output expander (IC704, IC701,
IC702 and IC703) to control various function in the unit.
7-1. Memory Circuit
IC607 has a flash memory with a capacity of 2M bits that
contains the transceiver control program for the CPU and
data such as transceiver channels and operating features.
This program can be easily written from an external de-
vices. Data, such as DTMF memories and operating status,
are programmed into the EEPROM (IC605).
16
CIRCUIT DESCRIPTION
+B
SB
IC103 IC104
8V REG 5V REG
5C
IC602
5V REG
5CM
8C
Q117
SW
8T
8TC
Q118
SW
8TB
8TBC
Q119
SW
8R
8RC
IC604
CPU
Fig. 9 Memory circuit
7-2. CPU Clock
The CPU clock is generated by VCXO (16.8MHz) and it is
fed through an inverter, IC603. This clock was divided into a
half cycle (1/2 frequency) at the internal CPU. The CPU fur-
ther divides this clock to utilize it as the various clocks.
X1
IC604
IC603
CPU
X2 INV
Fig. 10 CPU clock circuit
7-3. Shift Register
IC704, IC701, IC702 and IC703 is an interface IC for out-
put port expansion. It is used to expand the CPU (IC604)
output ports.
7-4. D/A Converter
IC715 and IC710 is used as a conventional semi-fixed-
resistor converter. It sets the following :
1) RX filter tuning
2) Transmission power tuning
3) Modulation level tuning
4) Audio power tuning
7-5. Key Input (Display unit)
K1 or K2 becomes High when any key is pressed (or en-
able signal on the optional circuit).
When K1 or K2 becomes High, to trigger the interrupt to
IC604 in order to start the key scan.
When the key scan starts, the output terminals IC901
(Q1~Q5) become Low. Only the key sensing circuit remains
High. When a key is pressed, the signal is routed through
K1 or K2 to the microprocessor. Then, the microprocessor
determines which key is pressed using this signals.
IC605
EEPROM
IC606
Address
decode
Flash
ROM
IC607
IC603 X501
INV VCXO
to PLL