Sharp LC-32LE440U, Service Manual

Page: 63 / 74

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RM172
NC/NC
R0805-P
PWM
RM175
47k
R0805-P
RM160
100K
R0805-P
RM174
390K 1%
R0805-P
CM151
1u/50V
BLON
CM158
0.1u/50V
+5V
CN201
16P 2.5mm
CON--JWT-A2501WV216PT
1
2
3
4
5
6
7
8
9
10
11
12
13
15
16
14
RM176
100K
R0805-P
ACD
ACD
FBI
BD+
QM111
MMBT4401
TRS--SOT23-BEC
1
3
2
+12V
PWM
RM161
10k
R0805-P
RM170
1M 1%
R1206
DIS
FaultI
UM107
LTV-817M-C
IC--LTV817M
3
1 4
2
RM168
1M 1%
R1206
+5V
PSON
RM163
1M 1%
R1206
ZD104
5.6V
DIO--ZD-1206
RM173
100K 1%
R0805-P
RM164
NC/NC
R0805-P
QM110
MMBT4401
TRS--SOT23-BEC
1
3
2
BLON
CN202
14P 2.5mm
CON--JWT-A2501WV214PT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
CM148
0.47u/50V
CM159
NC
C0805-P
RM165
10K
R0805-P
RM169
NC/NC
R0805-P
VCC1
CM152
1u/50V
+24V
BD101 is a rectifier in which there are 4 build-in diodes, inverting AC to DC. CP110,CP111
is used to smooth the wave from rectifier. FR801 is a fuse resistor to protect the following circuit
when inrush current is too large.
UM102 is a current-mode PWM controller with excellent power-saving operation, It features a
high-voltage current source to directly supply the startup current from two half-wave rectifier diodes
further to provide lossless startup circuit. Max start-up current for UM102 is 10mA, When current
flow from two half-wave rectifier diodes through RM107 and RM111 gets to HV pin to start up
UM102, Meanwhile, the VCC supply current is as low as 550uA thus most of the HV current is
utilized to change the VCC capacitor CM123, When Vcc (Pin6) reaches UVLO(on) threshold ,The
UM102 is powered on to start issuing the gate drive signal , the high-voltage current source is then
disabled ,and the Vcc supply current is provided from the auxiliary winding of the transformer PIN3.
UM102 Pin3 is protection PIN.RM101 are sense circuit, UM102 detects the MOSFET current,
from the CS in. When CS pin over 0.73V, the UM102 will enter auto-recovery type protection,
Presenting a hiccup mode. The gate-out will not resume switching until OCP falls below 0.67V.
UM102 Pin1 is OVP protection PIN.
It receives ON/OFF signal from secondary scalar