SG6858 Fairchild Semiconductor, SG6858 Datasheet - Page 10

• Manufacturer Part Number: SG6858
• Description: This highly integrated PWM controller provides several special enhancements designed to meet the low standby power needs of low-power SMPS
• Manufacturer: Fairchild Semiconductor

© 2008 Fairchild Semiconductor Corporation
SG6858 • Rev. 1.2.4
Typical Application Circuit (Flyback Converter for Printer Application)
Transformer
L
AC Input
N
0.22µF/300V
1
3
4
2
105Turns
Application
1A/250V
-
-
22Turns
0.25Φ*1
0.27Φ*1
Adapter
N
F
N3
A
N1
1
Core: EF-20
Primary-Side Inductance: 2mH (Pin1 to Pin3)
XC
R
1MΩ
1MΩ
1.2Ω
R
R
VDD
100kΩ
XC2
XC1
R
RI
FR103
D
VDD
3
2
18Turns
0.3Φ*2
FB
RI
Fairchild
Devices
SG6858
N2
+
10µF/50V
C
VDD
SG6858
GND
VDD
IN4007*4
1
5
Figure 17.
TP+
TP–
SENSE
GATE
Figure 18.
22µF/400V
+
Input Voltage Range
C
1.5MΩ
Bulk
6
4
R
Start
Schematic of Application Circuit
90~264V
Transformer Structure
66kΩ
47Ω
10Ω
R
R
10
UF1003
SN
G
AC
2.2nF
D
10nF/1KV
R
CY
SN
SN
C
R
SN
SENSE
N
P
PC817
SSP2N60
1.5Ω
N
47Ω 1nF
TL431
R
S
1%
SN2
MBR10100CT
D
R
C
SN2
560Ω
12V/1.25A (15W)
20kΩ 2.2nF
Output
R
N3: 2-4
N2: TP – - TP+
N1: 1-3
Shielding lead to Pin 2
Shielding lead to Pin 2
Shielding lead to Pin 2
F
680µF/16V
R
C
d
O1
C
+
F
C
O2
470µF/16V
+
38.3kΩ
R
10kΩ
R
1
2
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V
V
O
O
-
+