Fairchild FPS Series, Руководство по конструкции

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www.fairchildsemi.com/fps
FPS
™
Design Guide
Examples of Typical Application Circuits
Buck converters are ideal in low power applications where a single non-isolated power output is required. The FSDL0165RN buck
circuit was measured to have an excellent efficiency of over 77% for 15V/100mA, 15V/200mA and 15V/300mA levels over the
input voltage range. Buck circuits need a minimum load. This circuit was measured to have a power consumption of less than
350mW with a 15V/10mA output load. The low 50kHz switching frequency option helps to keep the switching losses low. Voltage
accuracy was measured to be around ±6% over line, load and temperature for one board. The fully avalanche rated MOSFET
provides additional robustness against voltage transients needed in those industrial applications where buck converters are commonly
used. The current mode control simplifies the feedback control circuit which supports both discontinuous and continuous current
modes. The device's frequency scaling helps to reduce the EMI caused by the switching.
• Buck converter using FSDL0165 has high efficiency and low standby power
– Ideal replacement for 50Hz transformer solutions
• FSDL0165RN has a fully avalanche rated MOSFET
– Robust performance under transient conditions
• Current mode control maximizes operating flexibility
– Low component count for feedback control circuit
– Same circuit operates in DCM and CCM
• Current limit may be lowered using an external resistor
• Good control of start-up surge
– Internal soft start feature helps
• Frequency modulation helps to reduce EMI
– Cost saving in external filter circuit
Fairchild Devices Description
FSDL0165RN Fairchild Power Switch (1.2A/50kHz)
BZX84C15 Zener Diodes (15V)
UF4004 Fast Recovery Diode (1A/400V)
BC337-25 General Purpose Transistor
5W Buck Converter Using FSDL0165RN
Typical Application – Industrial automation, household appliances, instrumentation
Vout 15V/300mA
Vin 120Vdc-385Vdc
1 2
VStr
5
Drain
7
Drain
8
GND
1
Vcc
2
VFB
3
Drain
6
ILim
4
1
2
C201
4.7uF
50V
+
Q200
BC337-25
CONN1
B2P3-VH
R205
470R
0.25W
L210
820uH
0.3A
C104
22nF
50V
D102
UF4004
D200
15V
0.5W
R104
5K1
0.25W
D210
UF4004
IC1
FSDL0165RN
C211
4.7uF
50V +
C101
22uF
400V
+
CONN2
B2P-VH
R204
100R
0.25W