ii.
Switching power ON
When Switching power receives the start order by 2
nd
pin of U41 (signal mark POWERON),
Then by Q25 2N7002 (signal mark V12_ON) and 1
st
pin of J11 to control Switching Power Model
pr12V (POWER STREE, refer to page 20 of schematic) and +24V , turn on the circuit of
+5V(signal mark VCC).
PWRON
Q15
2N7002
D
G
S
R298
5.6K
R300
2.2K
C482
.1
U41
SM5964C40J
RST
10
XTAL2
20
XTAL1
21
GND
22
PSEN
32
ALE/PROG
33
EA/VPP
35
VCC
44
P1.0
2
P1.1
3
P1.2
4
P1.3
5
P1.4
6
P1.5
7
P1.6
8
P1.7
9
P2.0/A8
24
P2.1/A9
25
P2.2/A10
26
P2.3/A11
27
P2.4/A12
28
P2.5/A13
29
P2.6/A14
30
P2.7/A15
31
P3.0/RXD
11
P3.1/TXD
13
P3.2/INT0
14
P3.3/INT1
15
P3.4/T0
16
P3.5/T1
17
P3.6/WR
18
P3.7/RD
19
P0.0/AD0
43
P0.1/AD1
42
P0.2/AD2
41
P0.3/AD3
40
P0.4/AD4
39
P0.5/AD5
38
P0.6/AD6
37
P0.7/AD7
36
V5up
V5up
R318
0_NC
C488
10U
1
2
R319
0
J11
1
2
3
4
5
6
7
8
9
10
11
12
13
V12IN
Vsub
V12_ON
Hi=POWER ON
To Switching Power
Lo=POWER ON
iii.
VCC ON/OFF
+5V (signal mark VCC) turn on when V12_ON=Hi, Every batches of digital board circuit would be
able to process Power ON procedure.
V12_ON
R340
10K
C510
470U
1
2
L123
PBY32-190
Q23
AP4435M
S1
1
S1
2
S1
3
G1
4
D1
8
D1
7
D1
6
D1
5
digital board circuit
To every batches of
+5V Always ON
Q24
3904
C
E
B
R343
10K
VCC
Vsub
VCC ON/OFF
iv.
CPU RESET
U18 PW328 CPU will output a Hi level to trigger other IC to reset when +5V, +12V and +24V start to
work. Then Firmware starts to read the data of U33 via U29 PWM2030 CPU and transmits data via
I2C BUS and sends control signal to run the TURN ON procedure
.
ViewSonic Corporation
Confidential - Do Not Copy
N4261w-1M
8
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