KX-HDV20RU - Panasonic PBX Service Manual (repair manual). Page 7

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7
KX-HDV20 Series  
4.2.
Circuit Operations
4.2.1.
Power supply Circuit
At first, this HDV20(DSS) module  must be connected to HDV230(at Upper DSS side).
The circuit converts the voltage supplied from HDV230 into the power supply of 3.3V and 5V by IC201 and IC202 (DC/DC Con-
verter IC).
D104
D102
DG
D101
D103
DG
DG
12V
L103
DG
VBUS_IN
VBUS_OUT
R157
R156
F101
JK101
6
5
4
3
2
1
7
JK102
6
5
4
3
2
1
7
L104
D106
D107
D108
Lower DSS
Upper DSS
-> HDV230
-> Lower HDV20
DG
C204
DG
DG
C211
C240
R210
IC202
2
N
I
V
8
S
S
3
W
S
4
1
D
N
G
5
B
F
7
N
E
1
T
O
O
B
6
P
M
O
C
9
2
D
N
G
C220
C207
DG
C203
DG
C213
R204
C217
C209
5V
C232
C222
R212
DG
R209
L203
L202
C221
R207
DG
C235
C206
DG
C225
C208
DG
12V
R214
C215
R203
C212
3.3V
DG
C231
C229
C239
DG
R208
C202
C214
R211
C218
C205
IC201
2
N
I
V
8
S
S
3
W
S
4
1
D
N
G
5
B
F
7
N
E
1
T
O
O
B
6
P
M
O
C
9
2
D
N
G
R202
C252
DG
R201
5V_DET
DG
C216
5V
R213
C227
TP_5V
C219
TP_3.3V
R205
R206
C210
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