39
2-3. SMPS BASIC OPERATING DESCRIPTION
1) Power supply block circuit
2) Initially starting operation
– When AC power supply is put in at first, the voltage which rectifies this.happens on the both Blocks of C806
This voltage flows through R806 and is the circuit which searchs the voltage of I801 V
in
TERMINAL (PIN No.#9) and
starts or stops operating I801.
– Turning on the power supply, CTRL circuit starts operating by the funtion of START circuit, when it is charged to C807
through starting resistance R806 and V
in
terminal voltage goes to 8V (TYP.)
– According to the multiplication(PRODUCT) of starting resistance R806 and C807, time is decided which CTRL citcuit
starts operating after putting AC input voltage. So, if the value of C807 is too high, It could be late for I801 to start.
– When CTRL circuit starts operating and the voltage of DRIVE wound wire (pin no #3) of T801 TRANS is up, I801
starts operating after rectification of D808 and C807.
– When the voltage of detect wound wire(pin no #4) T801 TRANS increases and is rectified through D807 and C809
and DC 32V is put in I801 sense(pin no #7), TRANS secondary voltage is established.
– When MAIN TR of power IC is off, energy which is charged to the primary is transtmitted through TRANS secondary
rectification DIODE.
PWC1
R804
2.2M(COMP)
1/2W
F801
AC 125V 4A
C801
O.1U(M)
AC250V
Z801
SVC2710
VARISTOR
L801
TLF-472BE
D802-D805
:1S1888
C802-C805
4700P 500V
R803
1 OHM 7W
CEMENT
R812
120K
1/2W
R806
36K
2W
8
9
10
11
12
13
14
16
15
7
6
5
4
3
2
1
R819
2.2
1/4W
R833
4.7K
1/4W
R807
18 1W
DR
S
B
C
E
OCP
1801
STR-S5707
Vin
SENSE
START UP
1
1
7
6
3
2
1
3
4
4
PRE REA
T.S.D
DSC
REF
OCP
R1
C1
C2 R2 C4
C3
PROPORTION
ORIVE
DVP LATCM
D810
BYV950
240(*200)
1/4W
R832
R809
0.27(F)
2W
R816
1K
1/4W
C822
1500P
50V
C824
4700P
AC400V
C823
3900P
630VPL
L803
MD-5
C808
220U
25V
R815
1.8K
1/4W
R813
100K
1/4W
C807
220U
25V
C809
10U
100V
D807
BYV95C
123V
15V
15V
8.5V
D811
BYV95C
D812
BYV95C
D813
BYW95C
D814
BYW95C
C827
1000P(HIKR)
2KV
T810
TSM-4242A3
C810
470U
16V
C812
470U
25V
C814
470U
25V
C828
0.01U
C815
100U
160V
D809
BYV95C
D808
BYV95C
D803
C803
D805
C805
D802
C802
D804
C804
C806
330U(LWF)
200V