Power Supply - Casio BN-10 Service Manual & Parts List

9-2. Power Supply

AC Adapter (7 V)
AD-A70140
FUSE (F601)
BLD2
to CPU
Battery (3 V)
BLD1
IC601
to CPU
Low battery
(2.1 V)
<POWER SUPPLY>
V5EXT: to MODEM
V5SYS: to CPU (Gate array etc.), DC/AC Inverter for
EL, Line receiver/driver
V2SYS: to CPU (Buzzer, Keys etc.)
V3SYS: to CPU (Oscillator etc.), Gate array, Memory,
TAB LSI for LCD
VLCO: to LCD
S D
: P channel MOS-FET
G
: Voltage detector
1. Refer to 9-1. Block Diagram.
2. Common mode coil (EF601) is used to prevent the emission of high frequency noise from AC
Adapter jack.
Common mode coil (EF601)
Voltage regulator
D606
IC611 (5 V)
D601
D-D Converter
IC603 (3 V 5 V)
Q624
Voltage regulator
IC602
Q623
Forced power off
(1.6 V)
APO:OFF
PORT4 from CPU
EVOL1~EVOL5
from CPU
D S
: N channel MOS-FET
G
— 45 —
Q602
D605
D607
Voltage regulator
IC605 (3 V) IC606 (2 V)
Q604
Q605
Voltage control
circuit
: Electronic variable ohm using analog switch
V5EXT (5 V)
APO:OFF
P5 (from CPU)
V5SYS
(5 V)
V2SYS
(2 V)
V3SYS
(3 V)
P1 to Gate array
Detection of low adapter
voltage (4.4 V)
VLCO
D604
20.5~23 V
VOUT
D-D
Converter
TH
: Thermistor (TH)