Casio SF-8350, Service Manual & Parts List

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1) Power supply chip SC371015FU
V1
V COMP2
VDD1
VDD2
VO1
V4
V3
V COMP1
VREG
V2
C8 C7
VDD
PDB
GATE ARRAY
VOT terminal
FROM
R10
R9
R8
(4.3 V ~ 4.7 V)
CR2032
CR2032 CR2032
The V comp1 and V comp2 outputs are the battery voltage detection outputs. According to
VDD1 and VDD2 voltages, V comp1 and V comp2 will change the status as follows:
V COMP 1
OUTPUTS STATUS " H " STATUS " L "
Memory battery
Main batteries
POWER SUPPLY CHIP
SC371015FU
13
14
15
16
21
8
1
2
19
7
10
9
12
11
6
18 20
17
+
+
22
GND1
GND2
31
When the batteries voltage When the batteries voltage
is more than 4.7 V. is less than 4.6 V.
When the batteries voltage When the batteries voltage
is more than 4.5 V. is less than 4.4 V.
V COMP 2
VSS(VREG) -3.5 -6.4
V1 +3.4 +3.1
V2 +2.5 +1.7
V3 -1.5 -3.6
V4 -2.5 -4.9
10-2. Power supply circuit
32
LCD DRIVE VOLTAGE Value (Approx.) [V]
Contrust : Min. Contrust : Max.
The IC SC371015FU is power supply chip for SF-
8350. When IC SC371015FU receives a Voltage
6V (CR-2032
×
2 pcs.) at the terminal VDD1(Pin
No.2), the regulated voltage VDD (4.3~4.7V) will
be applied to the VDD lines. The outputs Vss
(VREG) and V1~V4 are the LCD drive voltages.
When the terminal PDB becomes "H", those volt-
ages are generated by IC SC371015FU and ca-
pacitors C7 and C8 (ESCT1AY335R) and applied
to LCD driver IC MSM6385AV-Z-358B.
The resistors R8~R10 are used for dividing volt-
age V1~V4.