DER-75
2.4W Power Supply using LNK520P
September 12, 2005
ENTER TRANSFORMER CORE/CONSTRUCTION VARIABLES
Core Type
Core
Bobbin
AE
LE
AL
EE13
PC40EE13-Z
BE-13
0.171 cm^2
3.02 cm
1130 nH/T^2
517 mm^3
7.4 mm
Core Effective Cross Sectional Area
Core Effective Path Length
Ungapped Core Effective Inductance
Effective Core Volume
VE
BW
Bobbin Physical Winding Width
KCORE
551.5424 kW/m^3 Core losses per unit volume
Estimated transformer efficiency.
T(n)=(PSCU+PCORE/2)/POEFF. Re-iterate with n =
0.9147
Safety Margin Width
T(n)
M
NS
0.9
12
0.9
0 mm
Number of Secondary Turns
TRANSFORMER PRIMARY DESIGN PARAMETERS
Constant to account for reduction of inductance at
higher flux densities. (0.999<dLP<1.05)
Primary Inductance
Number of Primary Layers
Number of Bias winding Layers
Primary Winding Number of Turns
dLP
1.003
LP
L
2390.284 uHenries
3
3
1
LBIAS
NP
NB
ALG
BP
LG
1
113.6045
36.28176
185.2075 nH/T^2
3445.212 Gauss
0.097008 mm
Gapped Core Effective Inductance
Peak Flux Density (BP<3700)
Core Gap Length for primary inductance
Maximum Primary Wire Diameter including insulation to
give specified number of layers.
OD
DIA
0.195415 mm
0.154132 mm
Bare conductor diameter
Primary Wire Gauge (Rounded to next smaller standard
AWG value)
AWG
35 AWG
Primary Winding Current Capacity (200 < CMA < 500)
CMA
AWG_BIAS
414.8576 Cmils/Amp
32 AWG
TRANSFORMER SECONDARY DESIGN PARAMETERS
ISP
2.404628 Amps
Peak Secondary Current
Secondary RMS Current
ISRMS
IRIPPLE
0.954018 Amps
0.82447 Amps
Output Capacitor RMS Ripple Current
Secondary Wire Gauge (Rounded up to next larger
standard AWG value)
AWGS
DIAS
30 AWG
0.256342 mm
Secondary Minimum Bare Conductor Diameter
ODS
INSS
VSEC
0.616667 mm
0.180162 mm
0.096 Volts
Secondary Maximum Insulated Wire Outside Diameter
Maximum Secondary Insulation Wall Thickness
Voltage Drop across secondary winding
FEEDBACK CIRCUIT COMPONENTS
RFB
PRFB
7.065217 k-Ohms
37.375 mW
Feedback resistor
Losses in the Feedback resistor
ESTIMATED LOSSES IN POWER SUPPLY AND EFFICIENCY, LOW LINE
PCABLE
PSCU
PDIODE
PCAP
PBIAS
69.12 mW
182.0302 mW
268.8 mW
136.5226 mW
50.6 mW
Power loss in Output Cable
Transformer Secondary Copper Losses
Output Diode conduction loss
Power Loss in Feedback circuit
Conduction Losses in LinkSwitch calculated at 100C
Primary clamp losses
PCONDUCTION
PCLAMP
249.8913 mW
14.58 mW
PCORE
PBRIDGE
EFFICIENCY ESTIMATE
146.3907 mW
32.93465 mW
67.58908 %
Core Losses at peak Flux Density
Primary bridge rectifier losses
Estimated Power Supply Efficiency
ADDITIONAL OUTPUT
VX
VDX
NX
Auxiliary Output Voltage
Auxiliary Diode Forward Voltage Drop
Auxiliary Number of Turns
Volts
Volts
0
PIVX
0 Volts
Auxiliary Rectifier Maximum Peak Inverse Voltage
Power Integrations
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