Power Supply Circuits - Icom IC-24AT Service Manual
Dual band fm transceiver
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Also See for IC-24AT:
- Service manual (51 pages) ,
- Instruction manual (45 pages) ,
- Instruction manual (44 pages)
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3-6-4
CPU RESET
CIRCUIT
(LOGIC
UNIT)
IC3
detects the
5
V
line.
When
the
5
V
line
becomes
higher
than
the threshold voltage
of ICS,
ICS outputs
"HIGH"
as
the
interrupt signal.
While pushing
the
[FUNC]
switch,
power
is
turned
ON
that
applies
"HIGH"
to
the
reset port
of
the
CPU
(pin 76).
When
the
port
receives
"HIGH,"
the
CPU
is
initialized.
CPU RESET
CIRCUIT
3-7
POWER
SUPPLY
CIRCUITS
3-7-1
BATTERY CHARGING
CIRCUIT
(PRT
UNIT)
The
transceiver
has
a
constant-current regulated
circuit
for
charging the
connected
battery
pack.
Current
to
the
battery
pack
is
determined
the
base
voltage
of
Q2.
The
base
voltage
is
produced
with
R6, R8,
D6
and
feedback
voltage
from
the
battery
pack.
3-7-2
VOLTAGE
LINE
(REG
AND
lO
UNITS)
LINE
DESCRIPTION
Vcc
The
attached
battery
pack
or external
DC
power
voltages
are
passed
through
the
power
switch.
+5M
5
V
regulator
(IC1
on
REG
UNIT)
output.
+5
Current
amplified voltage
of
+5M.
Current
amplifier:
Q1
and
Q2
on
the
REG
UNIT.
+5S
Common
5
V
with
a power
as saver
function.
Control
signal
:
V5C
and U5C.
Current
amplifier:
C33
and
04
on
the
REG
UNIT.
V+5S
5
V
for
the
VHF
band
with
a power
saver
function.
Control
signal
:
V5C.
Current
amplifier:
06
on
the
REG
UNIT.
U+5S
5
V
for
the
UHF
band
with
a
power
saver
function.
Control
signal
:
U5C
Current
amplifier:
05
on
the
REG
UNIT.
V5C
5
V
for
the
VHF
band
with
a power
saver
function.
Control
signal
:
serial
data from
the
CPU.
Produced
location:
IC1
,
pin
14
on
the
lO UNIT.
U5C
5
V
for
the
UHF
band
with
a power
saver
function.
Control
signal
:
serial
data from
the
CPU.
Produced
location: IC1,
pin
13
on
the
lO UNIT.
R+5S
Receiver 5
V.
Control
signal
:
IC2, pins
4~7 on
the
lO UNIT.
Current
amplifier:
05
and
06
on
the
lO UNIT.
T+5
Transmitters
V.
Control
signal
:
IC2, pin
1 1
on
the
10 UNIT.
Current
amplifier:
01
and
02
on
the
lO UNIT.
UTS
UHF
transmitter
5
V.
Control
signal
:
IC2, pin
12
on
the
lO UNIT.
Current
amplifier:
03
on
the
lO UNIT.
VT5
VHF
transmitter
5
V.
Control
signal
:
IC2, pin
14
on
the
lO UNIT.
Current
amplifier:
04
on
the
10 UNIT.
HR5S
UHF
band
receiver
5
V
with
a
power
saver
function.
Control
signal
:
IC2, pins
4-6
on
the
lO UNIT.
Current
amplifier:
08
on
the
lO UNIT.
UB5S
Receiver 5
V
for
the
UHF
RF
circuit
with
a power
saver
function.
Control
signal
:
IC2, pin
6on
the
lO UNIT.
Current
amplifier:
01
on
the
MAIN
UNIT.
3-6
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