AN-9737 [FAIRCHILD]
Design Guideline for Single-Stage Flyback AC-DC Converter Using FL6961 for LED Lighting; 设计指南单级反激式AC- DC转换器采用FL6961 LED照明
| 型号： | AN-9737 |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | Design Guideline for Single-Stage Flyback AC-DC Converter Using FL6961 for LED Lighting |
| 文件： | 总11页 (文件大小：390K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
www.fairchildsemi.com
ANꢀ9737
Design Guideline for SingleꢀStage Flyback ACꢀDC
Converter Using FL6961 for LED Lighting
Summary
Basic Operation: High Power Factor
Flyback Converter
This application note presents singleꢀstage Power Factor
Correction (PFC) and focuses on how to select and design
the flyback transformer for 16.8W (24V/0.7A) solution for
universal input for LED lighting applications using FL6961.
The flyback converter using FL6961 operates in Critical
Conduction Mode (CRM) and has functions such as CC/CV
feedback circuit, softꢀstarting, and the cycleꢀbyꢀcycle current
limit for LED lighting applications.
The basic idea of achieving high power factor (PF) flyback
converter is to use a Critical Conduction Mode (CRM) PFC
controller. The conventional PFC IC, such as FL6961, has
constant onꢀtime and variable offꢀtime control method,
which means the input average current always follows the
input voltage shape.
Figure 1 shows the typical application schematic of singleꢀ
stage PFC topology. The main difference of normal CRM
boost converter is that singleꢀstage PFC doesn’t use a large
electrolytic capacitor after the full rectification diode.
Normally, the singleꢀstage PFC method uses a small
capacitor (C1 in Figure 1) to act as a noise filter to attenuate
highꢀfrequency components and doesn’t use the INV pin for
output voltage regulation.
Introduction
These days, engineers use various types of LEDs for general
lighting systems because of their long life, excellent
efficacy, price, environmental benefits, and requirements
from end users. At the same time, high power factor (PF),
isolation for safety, and constant current control (CC) for
constant LED color are becoming requirements.
Conventional regulation is the minimum power factor
correction for input power base above 25W, but many want
to reduce power ratings and the new EnergyꢀStar directive
for solidꢀstate lighting requires a power factor greater than
0.9 for commercial applications. Expect PF regulations to
become more stringent.
T1
BR
D3
C4
R5
R8
D2
R1
D1
C5
U101
R2
VCC
OUT
INV
1
2
8
7
Fuse
COMP
MOT
C1
R6
GND
ZCD
Q1
R3
3
4
6
5
R7
C2
CS
EMI filter
C3
R4
R8
Feedback
Figure 1. Simplified Schematic of HighꢀPower Factor Flyback Converter with FLS6961
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
ANꢀ9737
APPLICATION NOTE
Figure 2 shows typical waveforms of the simplified circuit
of a flyback converter with CRM. When the MOSFET (Q1)
turns on, the primary current in primary side linearly
increases and is clamped at a certain internal level because
the FL6961 doesn’t have cycleꢀbyꢀcycle current limit like a
conventional current mode control IC (such as FAN7527B).
Its peak level is determined by the primary magnetizing
inductance value and the fixed onꢀtime. Instead of the cycleꢀ
byꢀcycle primary current limit, the FL6961 has an overꢀ
current protection (OCP) function. If the current sensing
signal is larger than internal detection level, the FL6961
doesn’t get output signal for operating the MOSFET (Q1).
(NS) and naturally decreases to zero. The average current of
the secondary side is:
1 NP
IAVG(DIODE)
=
IPKtoff
(3)
2 NS
Since the diode forwardꢀvoltage drop decreases as current
decreases, the output voltage reflects the primary winding
and adds additional voltage due to overshoot made by
resonance between the leakage inductance on primaryꢀside
winding and parasitic capacitance on the MOSFET (Q1). As
a result, a superimposed voltage occurs on the MOSFET
during offꢀtime as:
MOSFET DrainꢀtoꢀSource Current)
DS
I
(
)
VMOSFET (off ) = VIN +VR +VOS
(4)
PK ( MOSFET
)
I
where VR is the reflected voltage and VOS is the voltage
overshoot term.
AVG (MOSFET
I
)
The reflected voltage, VR, is affected by the turns ratio
between the primary and secondary side of the transformer
and the output voltage, calculated as:
time
)
(Diode Current
D
I
PK ( DIODE
)
I
NP
VR =
VO
(5)
AVG (DIODE
I
)
NS
Figure 3 shows the ideal waveforms of the primaryꢀside
current at MOSFET (Q1) and the secondaryꢀside current at
the diode. The input peak and average current on the
primary side follows input voltage instantaneously.
Normally, secondaryꢀside current on the diode is larger than
the primary side because of the turns ratio.
time
DS
V
(MOSFET Voltage)
OS
V
R
V
IN
V
time
OFF
t
ON
t
S
t
Figure 2. Key Waveforms of Flyback Converter on
CRM
The FL6961 has a constant onꢀtime across the whole range.
The input average current always follows the peak input
current, as shown in the equation:
1
IAVG(MOSFET )
=
IPKtON
(1)
2
This is also proportional to the instantaneous input voltage.
This means the input current shape is always the same as the
input voltage shape. The reverse diode voltage is linearly
increased and is equal to:
Figure 3. Ideal Waveforms
NS
VPK (DIODE) = VO +VIN
(2)
NP
During the MOSFET offꢀtime, which is also the diode onꢀ
time; the input current instantly drops to zero, the diode in
the secondary side conducts, and the diode current linearly
decreases. The peak current of the secondary side is the
same as the multiplication of the primary peak current and
turns ratio between the primary side (NP) and secondary side
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
2
ANꢀ9737
APPLICATION NOTE
As a result, designers should consider two conditions before
component selection: voltage and current capacity on
primaryꢀside MOSFET(Q1) and secondaryꢀside diode (D3)
to make a stable system with margin.
Figure 4 shows a guide to deciding two components on the
boundary condition of flyback converter topology.
Figure 4. Boundary Conditions of Flyback Converter
Topology (Refer to AN-8025)
Design Example
A. Transformer Design
[W]
P = Io (Vo +Vd ) = 0.7(24+1) =17.5
A design guideline of 16.8W singleꢀstage flyback ACꢀDC
converter using FL6961 is presented. The applied system
parameters are shown in Table 1.
Step 4. Calculate the maximum input current, Imax
:
P
17.5
o
[A]
Iin(max)
=
=
= 0.168
Vminη
( 2 ×90)(0.82)
Table 1. System Parameters
Step 5. Calculate the MOSFET voltage drop, Vvd:
[V]
Parameter
Value
Vvd = Iin(max) RMOS = 0.168
Step 6. Calculate the primary voltage on transformer, Vp:
90V~265V
24V
Main Input Voltage Range, VAC(main)
Output Voltage, VOUT
0.7A
50kHz
1V
[V]
VP = Vmin −V vd= 127 − 0.168 ≈127
Vp=126.83 use 127
Output Current, IOUT
Minimum Switching Frequency at VAC(min)_pk
Diode Voltage Drop, Vd
Step 7. Calculate the primary peak current, Ippk
2TP
2(20×10−6 )(17.5)
Vpton(max) 0.82(127)(7×10−6
:
1ꢁ
MOSFET On Resistance, RMOS
Window Utilization
[A]
I ppk
=
=
= 0.96
0.4
η
)
0.82
0.35
0.35
Target System Efficiency
Step 8. Calculate the primary rms current, Iprms
:
Maximum Duty at Vac(min)_pk
Operating Maximum Flux Density
(7×10−6 )
ton
[A]
I prms = I ppk
= 0.96
= 0.32
3T
3(20×10−6 )
0.5%
Regulation, α
Note:
Step 9. Calculate the required minimum inductance, L:
1. Regulation is strongly related with the copper loss and
0.5% regulation means 0.084W loss on transformer.
127(7×10−6 )
Vpton(max)
[mH]
L =
=
= 0.926
I ppk
0.96
There are many ways to decide core and coil size and turns,
such as using AL value and following common practices. In
this note, use the Kg value related with the core geometry to
find optimum core and coil information.
L=0.926[
m
H] use 1[mH]
Step 10. Calculate the energyꢀhanding capability in wattꢀ
seconds, wꢀs:
Step 1. Calculate the total period, T:
1
LI p2pk
(1×10−3 )(0.962 )
[wꢀs]
[ꢂs]
ENG =
=
= 0.0004608
T = = 20
2
2
f
Step 2. Calculate the maximum onꢀtime at MOSFET in
primary side.
Step11. Calculate the electrical conditions, Ke:
Ke = 0.145PBm2 ×10−4 = 0.145(17.5)(0.352 )×10−4 = 0.00003108
Step 12. Calculate the core geometry, Kg:
ton = TDmax = (20×10−6 )(0.35) = 7
[ꢂs]
Step 3. Calculate the output power:
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
3
ANꢀ9737
APPLICATION NOTE
(ENG)2
(0.0004608)2
[A/cm2]
Wa Ku
Nnew
0.4283×0.4
[cm5]
AW (B)
=
=
= 0.002315
Kg =
=
= 0.0136
74
Keα
0.00003108(0.5)
Step 23. Calculate the skin depth at expected operating
frequency at low input voltage. The skin depth is the radius
of the wire.
Step 13. See Table 2 for core size.
To prevent core saturation, select a little big core after
comparing two Kg values: calculate value at Step 12 vs. the
existing value in Table 2.
6.62
6.62
50×103
[cm]
γ
=
=
= 0.02960
f
The PQꢀ42016 has a little bit big Kg value (0.01327) in
Table 2 with 2500 permeability (ꢁi).
Step 24.Calculate the required wire area under considering
skin depth :
Step 14. Calculate the current density, J.:
[cm2]
2
WireA =
π
(r ) = 0.0027535
4
4
[A/cm2]
2( ENG ) × 10
2(0.0004608 ) × 10
0.35 (0.2484 )( 0 .4)
J =
=
= 265
Bm AP K u
Step 25. Select a wire size with the required area from Table
4. If the area is not within 10% of the required area, then go
to the next smallest size.
Step 15. Calculate the required wire area. AW(B)
:
[cm2]
I rms
J
0.32
265
AW
=
=
= 0 .001207
AWG=#23
AW(B)=0.00259[cm2]
( B )
Step 16. Calculate the number of turns, N:
ꢁꢂ/cm=666
W a K u
Aw ( B )
0.4283 × 0.4
0.001207
[T]
N =
=
= 141 .93
Step 26. Calculate the required number of primary strands,
Snp:
N=141.93; use 142 turns.
Step 17. Calculate the required gap, lg:
Aw(B)
0.002315
0.00259
Snp
=
=
= 0.8938
WireA
0.4π
(N)(ꢀI)×10−4 0.4
π
(142)(0.96)×10−4
[cm]
lg =
=
= 0.0489
This means that the selected wire from the Step 25, AWG23,
is enough or has enough margins for supplying the primaryꢀ
side current on the flyback converter.
ꢀBm
0.35
Step 18. Calculate the new turns using a gap from Step 15.
Step 27. Calculate the secondary and auxiliary turns, Ns
MPL
ꢁi
(Ac )
3.74
1×10−3 (0.0489 +
)(108 )
L(lg
+
)
Naux
:
[T]
2500
0.4π (0.58)
N =
=
= 83.153
0.4
π
N p (Vo +Vd )(1− Dmax
)
74(24 +1)(1− 0.35)
( 2 ×90)(0.35)
Ns =
=
= 27.05
=17.31
(Vp Dmax
)
N=83.153; use 83[T].
Ns=27.05; use 27.
N p (Vo +Vd )(1− Dmax
where ꢀi is permeability of selected core material and
MPL is Magnetic Path Length of selected core.
)
74(15 +1)(1− 0.35)
Naux
=
=
(Vp Dmax
)
Step 19. Calculate the fringing flux, F:
( 2 ×90)(0.35)
lg
2G
0.0489 2(1.001)
ln ) = 1.238
Naux=17.31; use 17.
Step 28. Calculate the secondary peak current, Ispk
F = (1+
ln
) = (1+
lg
0.0489
Ac
0.58
:
where G is window height of selected core.
2Io
2(0.7)
[A]
Ispk
=
=
= 2.153
(1− Dmax
)
1− 0.35
Step 20. Calculate the new turns, Nnew
:
0.0489×1×105
(0.4 )(0.58)(1.238)
Step 29. Calculate the secondary rms current, Isrms
:
lg L
)(Ac )F(10−8
[T]
N =
=
= 73.6
(0.4π
)
π
(1− Dmax
)
(1− 0.35)
[A]
:
Isrms = Ispk
= 2.153
=1.0021
3
3
Nnew=73.6; use 74.
Step 30. Calculate the secondary wire area, Asw(B)
Step 21. Calculate the AC flux density in Tesla, BAC
:
IPK
0.96
Irms 1.0021
(0.4π
)N(
)F(10−4
)
(0.4π
)(74)(
)(1.238)(10−4
)
[cm2]
ASW (B)
=
=
= 0.003781
= 0.113 [T]
2
lg
2
Bac
=
=
J
265
0.0489
Step 31. Select a wire size with the required area from Table
4. If the area is not within 10% of the required area, go to
the next smallest size.
Step 22. Calculate the new wire size, AW(B)
:
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
4
ANꢀ9737
APPLICATION NOTE
AWG=#22
C. Sensing Resistor
AW(B) =0.003243[cm2]
ꢁꢂ/cm=531.4
The CS pin of FL6961 has overꢀcurrent protection (OCP)
over the whole operating period and its internal clamping
level, VLIMIT, is 0.8V.
Step 32. Calculate the required number of primary strands,
Snp:
Asw(B)
0.003243
0.00259
Snp
=
=
=1.2521
WireA
This requires the AWG21 wire with two strands for
secondaryꢀside winding on the flyback converter.
Adapted Core Size
PQꢀ42614
AWG
23
Primary
74
27
Turns
Secondary
Auxiliary
22/ 2 Strands
17
Estimated gap[mm]
0.489
Figure 5. Switching Current Limit
B. MOSFET and Diode Selection
Normally, it is reasonable to set the OCP level to 1.5 times
higher than the peak current at primary side.
Step 33. Calculate the maximum voltage of MOSFET drain
voltage at primary side:
3TP
N
VMOSFET(off ) =VIN +VR +VOS =VIN + P VO +VOS = 490.54
[V]
ILIMIT = 1.5IPPK
=
= 1.44
η
Vpton(max)
NS
where VOS is assumed ~50V and its peak can degrade
external snubber circuit performance. This means a 600V
MOSFET can be used with some margin. Minimum
requirements of the MOSFET are summarized below.
Calculate the sensing resistor as:
0.8
[
Ω ]
Rsensin g
≤
= 0.55
ILIMIT
D. Voltage and Current Feedback for CC/CV
Function
Current Rating [A]
Calculation +20% Margin Calculation
0.96 1.152 490.54
Voltage Rating [V]
+20% Margin
588.65
The constant voltage and current output is adapted by
measuring the actual output voltage and current with
external passive components and an op amp in the
evaluation board. Because the output loads, the High
Bright LED (HB LED) and passive components are
effected by ambient temperature. Use the feedback path
for stable operation.
Step 34. Calculate the maximum voltage of diode at
secondary side:
NS
NP
27
74
[V]
VPK (DIODE ) = VO +VIN
= 24 + 265 2
= 160.74
This means a 200V diode can be used with some margin.
The minimum requirement of the secondary diode as
summarized below.
Current rating [A]
Calculation +20% Margin Calculation
2.153 2.584 160.74
Voltage rating [V]
+20% Margin
192.88
Figure 6. Feedback Circuit for CC/CV Operation
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
5
ANꢀ9737
APPLICATION NOTE
E. SoftꢀStart / Overshoot Prevention Function
Normally, the CC block is dominate over the CV block in
steady state and the CV block acts as the OverꢀVoltage
Protection (OVP) at transient or abnormal mode, such as noꢀ
load condition.
Normally, the High Bright (HB) LED has a forwardꢀcurrent
limitation to prevent the LED burnꢀout due to overꢀpower
dissipation. Thererfore, the output overshoot function is
needed through the whole operating period. Though there
are CC/CV blocks for output regulation, those blocks do not
operate in transient modes, because they block have a long
response time and cannot act instantly. Figure 7 shows the
output voltage overshoot compression method using diode
and resistor. The current flows through resistor, R9, and
diode, D204, at startup, which is the period before activating
the CC/CV block, and then decrease at steady state. The
quantity of byꢀpassing current goes into the feedback block
on the control IC, FL6961, and controls the output power
gradually.
The output signal of CC block is determined as:
Vsensin g _ CC Vref
Vsensin g _ CC Vref
1
VO _ cc = R4 (
−
) +
(
−
)dt
∫
R2
R3
C1
R2
R3
where the Vsensing_CC means the sensing voltage from the
sensing resistor (R1) and its values is as:
Vsensin g _ CC = Io × R
1
The output signal of CV block is determined as:
R6
R
R6
VO _CV = (
)Vsensin g _CV
+
8 [(
)
R5 + R6
R7 R5 + R6
1 1
R6
Vsensin g _CV −Vref ]+
(
Vsensin g _CV −Vref )dt
∫
C2 R7 R5 + R6
where the Vsensing_CV means the output voltage on this
circuit and this voltage is divided by two resistors, R5 and
R6, and connected to nonꢀinverted pin at the op amp.
R6
Normally, set this divided voltage,
, to
)Vsensin g _ CV
(
R5 + R6
Vref
or a little bit smaller value in steady state condition
because the main role of this block is overꢀvoltage
protection. There are more highꢀvoltage transfers to the
output stage at transient or an abnormal case such as overꢀ
voltage output condition than in the steady state.
Figure 7. SoftꢀStart / Overshoot Prevention Method
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
6
ANꢀ9737
APPLICATION NOTE
Table 2. Various Core Types and Size
MLT
[cm]
MPL
[cm]
Wa
Ap
Kg
Part #
G[cm] AC [cm]
Perm
AL
Manufacturer
[cm2]
[cm4]
[cm5]
RMꢀ42316
PQꢀ42610
PQꢀ42614
PQꢀ42016
EPCꢀ25
4.17
5.54
5.54
4.34
4.930
7.77
4.78
3.80
2.94
3.33
3.74
5.92
5.19
5.69
1.074
0.239
0.671
1.001
1.800
0.356
1.86
0.640
1.05
0.454
0.2900
0.017820
0.00937
0.01200
0.01327
0.01438
0.018416
0.01917
2500
2500
2500
2500
2300
2500
1800
2200
6310
4585
2930
1560
4103
1800
Magnetics
Magnetics
Magnetics
Magnetics
Magnetics
Magnetics
Philips
0.1177 0.1235
0.3304 0.2343
0.4283 0.2484
0.8235 0.3810
0.3613 0.3595
0.6789 0.3944
0.709
0.580
0.4640
0.9950
0.5810
EIꢀ44008
EFDꢀ25
Table 3. PQꢀ42016 Core Dimensions
(Magnetics: http://www.magꢀinc.com/home/AdvancedꢀSearchꢀResults?pn=42016
Table 4. Wire Table
Bare Wire Area
Heavy Insulation
AWG
ꢁꢂ/cm
Cm2
CIRꢀMIL
1024.0
812.30
640.10
510.80
404.0
Cm2
Turns/cm
11.37
12.75
14.25
15.82
17.63
19.8
Turns/cm2
98.93
20
21
22
23
24
25
26
27
28
29
0.005188
0.004116
0.003243
0.002588
0.002047
0.001623
0.001280
0.001021
0.008048
0.0006470
332.3
418.9
0.006065
0.004837
0.003857
0.003135
0.002514
0.002002
0.001603
0.001313
0.0010515
0.0008548
124.0
531.4
155.5
666.0
191.3
842.1
238.6
320.40
252.80
201.60
158.80
127.70
1062.0
1345.0
1687.6
2142.7
2664.3
299.7
22.12
24.44
27.32
30.27
374.2
456.9
570.6
701.9
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
7
ANꢀ9737
APPLICATION NOTE
Schematic
FL6961
Figure 8. Schematic
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
8
ANꢀ9737
APPLICATION NOTE
Bill Of Materials
Item
Part
Value
Quantity
Description (Manufacturer)
Number Reference
1
2
3
4
5
6
7
8
9
U101
U102
FL6961
FOD817
1
1
1
1
1
1
1
1
2
CRM PFC Controller (Fairchild Semiconductor)
OptoꢀCoupler (Fairchild Semiconductor)
U201
KA431
Shunt Regulator (Fairchild Semiconductor)
U202
KA358A(LM2904)
FQPF3N80C
DF04
Dual Op Amp (Fairchild Semiconductor)
Q101
800V/3A MOSFET (Fairchild Semiconductor)
D101
1.5A SMD BridgeꢀDiode (Fairchild Semiconductor)
1000V/1A UltraꢀFast Recovery Diode (Fairchild Semiconductor)
400V/1A Fast Recovery Diode (Fairchild Semiconductor)
200V/3A UltraꢀFast Recovery Diode (Fairchild Semiconductor)
D102
RS1M
D103
RS1G
D201,D204
EGP30D
D202,D203,
D205,D206
10
11
LL4148
82Kꢁ
3
3
GeneralꢀPurpose Diode (Fairchild Semiconductor)
SMD Resistor1206
R101,R102,
R103
12
13
14
15
16
17
18
19
20
R104
R105
120kꢁ
10Kꢁ
20Kꢁ
9.1kꢁ
47ꢁ
1
1
1
1
1
1
1
1
2
SMD Resistor1206
SMD Resistor1206
SMD Resistor1206
SMD Resistor1206
SMD Resistor 1206
SMD Resistor 1206
2W
R106
R107
R108
R109
10ꢁ
R110
220Kꢁ
30Kꢁ
1ꢁ
R111
SMD Resistor 1206
SMD Resistor 1206
R112,R113
R201,R202,
R203
21
1ꢁ
3
SMD Resistor 1206
22
23
24
25
26
27
28
29
30
31
32
R204
R205
R206
R207
R208
R209
R210
R211
R212
R213
R214
2.2ꢁ
4.3Kꢁ
1.5Kꢁ
30Kꢁ
51Kꢁ
33Kꢁ
3.9Kꢁ
120Kꢁ
47Kꢁ
4.7Kꢁ
47Kꢁ
1
1
1
1
1
1
1
1
1
1
1
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
SMD Resistor 0806
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
9
ANꢀ9737
APPLICATION NOTE
Bill Of Materials (Continued)
Item Number
Part Reference
Value
Quantity
Description (Manufacturer)
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
C101
C102
100nF/250V
47nF/250V
100nF/630V
33µF/35V
2.2nF/1kV
2.2µF
1
1
1
1
1
1
1
1
2
1
1
1
2
1
1
1
1
1
X – Capacitor
X – Capacitor
C103
Film Capacitor
Electrolytic Capacitor
YꢀCapacitor
C104
C105
C106
SMD Capacitor 0805
SMD Capacitor 0805
SMD Capacitor 0805
Electrolytic capacitor
SMD Capacitor 0805
SMD Capacitor 0805
Electrolytic Capacitor
Line Filter
C107
30pF
C108
100nF
C201,C202
C203
470µF/35V
1µF
C204
470nF
C205
10µF/35V
80mH
LF101,LF102
L101
27µH
Line Filter
L102
6.8µH
Line Filter
L201
5µH
Output Inductor
Fuse
F101
1A/250V
PQꢀ42016
T1
1mH
© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
10
ANꢀ9737
APPLICATION NOTE
Related Datasheets
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2. A critical component is any component of a life support device
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© 2011 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 4/13/11
www.fairchildsemi.com
11
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