Fairchild FPS Series, Design Manual

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www.fairchildsemi.com/fps
FPS
™
Design Guide
Examples of Typical Application Circuits
Multiple output flyback converters are used in applications where power is supplied to diverse sub-systems such as drives, tuners,
audio stages and complex processor and logic circuits. Primary side regulation is used in this circuit to reduce the total cost. For this
power level and above it is more cost effective to use four diodes in a full bridge configuration than a single diode with a larger
capacitor. For high current outputs it is recommended to use a Schottky diode on the secondary side.
• Primary side regulation reduces system cost
– Cross regulation is good, total regulation worse than with an optocoupler solution
• Frequency modulation approach minimizes EMI circuitry
– Common-mode choke can be replaced by a simple dual capacitor, dual low cost inductor circuit
• Overload protection circuit distinguishes between temporary and permanent overload
– Device does not shut down during load surge conditions from drive unit
– Inherent short circuit protection
Fairchild Devices Description
FSD210M Fairchild Power Switch (0.3A/134kHz)
BZX84Cxx Zener Diodes (10V, 12V)
P6KE200 Transient Voltage Suppressor (600W/200V)
SB140 Schottky Diode (1A/40V)
1N4935 Fast Recovery Diode (1A/200V)
1N4937 Fast Recovery Diode (1A/600V)
UF4007 Fast Recovery Diode (1A/1000V)
1N4007 General Purpose Diode (1A/1000V)
1N4148 General Purpose Diode (10mA/100V)
BC546B General Purpose Transistor
10W Multiple Output Isolated Flyback Using FSD210 with Primary Side Regulation
Typical Application – Set top boxes, decoders and small DVD players
195V-265VAC input
10W output
Lp = 2200uH EF20 (on Epcos N67 core)
Primary 81 turns
Vcc 7 turns
5V 3 turns
3.3V 2 turns
12V 9 turns
22V 11 turns
VFD 2 turns
fsw = 134kHz
Vcc
5
DRAIN
7
VSTR
8
GND
1
GND
2
GND
3
VFB
4
1 2
12
11
10
9 5
4
6
2
1
7
8
3
D15
1N4007
L1
2.2mH
0.09A
C14
100nF
50V
D17
12V
C11
22nF
50V
C9
100uF
16V +
D8
1N4148
C5
10uF
50V
+
D2
1N4007
L2
2.2mH
0.09A
C7
4.7uF
400V
+
FS1
230V/1A
D1
1N4935
D5
BA159
R10
120R
D14
1N4007
D16
SB140
C2
22uF
35V
+
D6
1N4007
L3 FERRITE BEAD
C15
10uF
16V
+
IC1
FSD210M
Q4
BC546B
PL3
B2P3-VH
C8
1uF
50V
D3
P6KE200
C12
100uF
16V +
D12
10V
0.5W
D9
1N4148
D7
12V
C13
100uF
16V +
D13
SB140
C6
4.7uF
400V
+
D10
1N4935
C4
10uF
16V
+
TR1
EF20 EPCOS 12Pin
R11
560R
R3
68R
R101
R2
100R
C10
33nF
50V
C3
100nF
50V
C1
2.2nF
Y1
R1
100R
D4
1N4935
0
0
0
0
0
0
0
0
+3.3V/0.5A
+12V/50mA
FL2/VFD
FL1/VFD
+12VA/50mA
+5V/0.5A
-22V/50mA
-12VA/50mA