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| Input data |
L= |
1.5 |
uH |
Inductance |
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Ipkx= |
18.0 |
Apk |
Inductor maximum peak current |
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Ippx= |
8.0 |
App |
Max peak to peak current |
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Idcx= |
14.0 |
Aavg |
Max avg current |
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Iacx= |
2.3 |
Arms |
Max AC rms ripple current |
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f= |
140 |
kHz |
Frequency for B variation |
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Icd= |
6.0 |
A/mm2 |
Current density |
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Smp= |
1.3 |
mm |
Safety margin, Pri/HF winding, mm |
RM 12 |
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Sms= |
1.3 |
mm |
Safety margin, Sec/LF winding, mm |
RM 12 |
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Whm= |
10.0 |
mm |
Min winding height, mm |
RM 12 |
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Wwm= |
14.0 |
mm |
Min winding width, mm |
RM 12 |
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Ltm= |
47.0 |
mm |
Min turn length |
RM 12 |
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Ltn= |
61.0 |
mm |
Average turn length |
RM 12 |
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Am= |
125 |
mm2 |
Magnetic core area, minimum |
RM 12 |
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Ae= |
146 |
mm2 |
Magnetic core area, effective |
RM 12 |
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le= |
56.6 |
mm |
Magnetic path length |
RM 12 |
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Vm= |
8,340 |
mm3 |
Magnetic volume |
RM 12 |
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Vt= |
8,340 |
mm3 |
Total volume |
RM 12 |
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ALo= |
5,050 |
nH/T2 |
AL, ungapped core, no DC bias |
RM12-3F3 |
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ur= |
1,558 |
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u, ungapped core, no DC bias |
3F3 |
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Bmax= |
0.30 |
T |
Maximum flux density |
3F3 |
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uh= |
99.0 |
% |
Permeability @ Hpk |
3F3 |
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| Output data |
L0= |
5.1 |
uH |
Zero bias, no gap Inductance |
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Lb= |
5.0 |
uH |
Peak current bias, no gap Inductance |
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L= |
1.5 |
uH |
Peak current bias, gapped Inductance |
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Nomin= |
0.7 |
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Minimum Number of turns |
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No= |
1 |
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Number of turns, chosen |
> 1.2 x Nomin |
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Bpk= |
0.22 |
T |
Actual peak flux density |
OK |
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AL= |
5,000 |
nH/T2 |
Core Al, ungapped, bias @ Hpk |
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ALg= |
1,500 |
nH/T2 |
Required core AL, gapped, bias @ Hpk |
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ue= |
463 |
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Required relative permeability, gapped
core |
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Gap0= |
0.09 |
mm |
Core gap, no fringe effect |
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Gap= |
0.09 |
mm |
Core gap, closer to real |
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dB= |
41 |
mT |
Half of B peak to peak variation |
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Hpk= |
247 |
A/m |
Magnetizing Force, SI |
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Hpk= |
3 |
Oe |
Magnetizing Force, USA |
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Inductor Core Loss |
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| Intermediate |
P3= |
13 |
mW/cm3 |
Philips Ferrite 3F3 material |
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| data |
Pml= |
96 |
mW/cm3 |
Allied Signal MicroLite 245 material |
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Pm60= |
90 |
mW/cm3 |
Magnetics MPP 60u material |
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Pm125= |
156 |
mW/cm3 |
Magnetics MPP 125u material |
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Pk= |
230 |
mW/cm3 |
Magnetics Kool-Mu material |
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Ppl= |
299 |
mW/cm3 |
Allied Signal PowerLite material |
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Phf= |
409 |
mW/cm3 |
Magnetics High Flux 60u material |
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P18= |
748 |
mW/cm3 |
Micrometals Iron Powder 18 material |
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Rthm= |
13.4 |
°C/W |
Rth, toroid, open wound, natural
convection |
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| Output data |
P3= |
0.1 |
W |
3F3 |
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Pml= |
0.8 |
W |
MicroLite 245 |
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Pm60= |
0.8 |
W |
MPP 60u |
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Pm125= |
1.3 |
W |
MPP 125u |
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Pk= |
1.9 |
W |
Kool-Mu |
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Ppl= |
2.5 |
W |
PowerLite |
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Phf= |
3.4 |
W |
High Flux 60u |
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P18= |
6.2 |
W |
Iron Powder 18 |
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dT3= |
1 |
°C |
Core Temperature Rise, 3F3 |
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dTml= |
11 |
°C |
Core Temperature Rise, MicroLite 245 |
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dTm60= |
10 |
°C |
Core Temperature Rise, MPP 60u |
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dTm125= |
17 |
°C |
Core Temperature Rise, MPP 125u |
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dTk= |
26 |
°C |
Core Temperature Rise, Kool-Mu |
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dTpl= |
33 |
°C |
Core Temperature Rise, PowerLite |
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dThf= |
46 |
°C |
Core Temperature Rise, High Flux 60 |
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dT18= |
84 |
°C |
Core Temperature Rise, Iron Powder 18 |
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| This worksheet calculates a inductor (number of turns and core
loss). |
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| The operating core temperature is assumed to be 100°C. |
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| Minimum loss would be at 80-90°C. |
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| Maximum core operating temperature should be <140°C. |
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| The accuracy of the formulas is expected to be ±10% for core
loss, and ±25% for temperature rise. |
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| SMPS Power Supplies, Inc. |
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| Doing The Right Thing Is The Right Thing To Doä |
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| www.SMPS.com |
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| www.GoToPower.net |
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| Copyright © 1998-2005 SMPS Power Supplies,
Inc. All rights reserved. |
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| Copyright © 1990-1997 LCD Consulting |
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| Copyright © 1979-1989 Constantin Darius Livescu |
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