TK-7180H/7182H
22
6. Power Supply Circuit
The block diagram of the power supply circuit is shown in
Figure 6.
Power is always supplied from +B to the circuit (5M, +B)
that is always started and the circuits (SB, 8C, 5E, 8T, 8R, 5C,
5R) controlled by the CPU (IC404). When +B is supplied to
the transceiver, Q801, D805 and IC805, regulate the voltage
(5M) which is supplied to the circuit around the CPU. The
CPU starts.
When the CPU detects that the +B voltage is higher than
the voltage prescribed by IC802, the transceiver power (SB)
is turned ON by controlling the SBC signal (Low: transceiver
power OFF, High: transceiver power ON).
Fig. 6
Power supply circuit
CIRCUIT DESCRIPTION
D804
DET
Q802
SW
Q807
SW
IC803
AVR
IC807
AVR
Q803
SW
Q806
SW
Q804
SW
Q808
SW
IC804
AVR
Q805
SW
Q809
SW
Q810
SW
Q811
SW
IC805
AVR
IC802
DET
IC801
DET
Q801,D805
REG
5M
SBC
CN401
CPU
Flash memory
EEPROM
Ext-I/O
CPU #17
: RST1
RTC IC
TK-7180H
only
CPU #24
: INT
Power supply : 10.8~15.7V
+B
SB
8C
8T
5E
TXC
8R
RXC
5C
5R
RXC
Final AMP
Audio AMP, PA connector
Panel block, D-sub block
Internal option
Panel block
Internal option
TX-drive
APC block
ANT SW
IF block
VCXO, VCO, PLL IC
IF detection IC
DC/DC converter
D/A converter
MIC AMP, AQUA-L
AF block
IF block
F801
5A
The CPU controls the TXC signal (Low: Transmission sys-
tem power OFF, High: Transmission system power ON) dur-
ing transmission to supply power (8T) to the transmission cir-
cuit. The CPU controls the RXC signal (Low: Reception sys-
tem power OFF, High: Reception system power ON) during
reception to supply power (8R, 5R) to the reception circuit.
When the CPU detects the PSW (Power Switch) signal,
IGN (Ignition Sense) signal or INT signal, it controls the SBC
signal and turns the transceiver power (SB) OFF.
If +B is not provided to the transceiver, power is supplied
to only the RTC IC (IC402) through the secondary battery con-
nected with CN401 to back up the clock.