Fairchild FPS Series, Руководство по конструкции

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www.fairchildsemi.com/fps
FPS
™
Design Guide
Examples of Typical Application Circuits
24V/100mA output
Lp=1700uH 100/25 EF20 (on Vogt Fi324 core)
85V-265VAC from appliance
input filter stage
fsw=134kHz
1
4
8
5
1
2
VCC
5
DRAIN
7
VSTR
8
GND
1
GND
2
GND
3
VFB
4
1
2
2
3
1
1
2 3
4
FS1
230V/250mA
C206
33nF
50V
C104
33nF
50V
T1
VOGT EF20
D201
SB180
R101
C102
2.2nF
1000V
C300
YCAP
250V
R201
1K
0.25W
D100
1N4007
C101
10uF
400V +
CONN1
B2P3-VH
R202
1K
0.25W
IC1
FSD200M
C103
1uF
50V +
R203
3K
0.25W
R204
91K
0.25W
CONN2
B2P-VH
L100
IC3
KA431LZ
IC2
H11A817A.W
D102
UF4007
D101
1N4007
R102
100K
0.6W
R205
11K
0.25W
C201
100uF
50V
+
C100
10uF
400V +
L101
In this converter, isolation is provided by the transformer and the H11A817A optocoupler. Output accuracy is improved using the
KA431 voltage reference. The values R201, R203, C206, R204 and C104 set the closed loop control parameters and performance.
Using a Schottky diode is a cost-effective method of improving efficiency where needed.
• Feedback circuit using KA431 reference and H11A817A optocoupler
– More accurate regulation over line, load and temperature than with a Zener diode
• Schottky diode used in output stage
– Cost-effective means of improving efficiency
• Integrated soft start function
– Prevents power surges during switch-on time
Fairchild Devices Description
FSD200M Fairchild Power Switch (0.3A/134kHz)
KA431 2.5V Reference (2.5V)
H11A817A Transistor Optocoupler
SB180 Schottky Diode (1A/80V)
UF4007 Fast Recovery Diode (1A/1000V)
1N4007 General Purpose Diode (1A/1000V)
2.5W Single Output Isolated Flyback Using FSD200 with KA431 Reference
Typical Application – Isolated main or standby power supplies for household appliances