by : george orenchak tsc ferrite international · soft ferrite advantages, capabilities &...
TRANSCRIPT
Soft Ferrite Advantages, Capabilities & Markets 1997 Soft Ferrite Users Conference
By : George Orenchak
TSC Ferrite International
Soft Ferrite Advantages, Capabilities & Markets Slide 1
Soft Ferrite is the general term to a class of ceramic, electromagnetic materials ν They have a homogeneous cubic spinel
crystalline structure ν Are composed of iron oxide with divalent
metal oxides ν MnZnFe2O4 or NiZnFe2O4
Soft Ferrite Advantages, Capabilities & Markets Slide 2
Advantages of Soft Ferrite ν High Resistivity = low eddy current loss = high usable
frequency ranges ν High Magnetic Permeability = high induction in minimal
space ν Versatility of core shapes = satisfies magnetic
requirements in minimal space ν Light Density = light weight ν Low Cost Relative to Alternative Materials
Soft Ferrite Advantages, Capabilities & Markets Slide 3
NiZn Ferrite are best for > 2 MHz
MnZn Ferrite are best for 20 KHz to 2 MHz
80% NiFe is best for 2 KHz to 20 KHz
50% NiFe is best for 300 Hz to 2 KHz
3% SiFe is best < 300 Hz
10 100 1000 10000 100000 1000000 10000000100
1000
10000
100000
Frequency (Hz)
Pe
rfo
rma
nce
Fa
cto
r (T
es
la H
ert
z)
3%SiFe 50%NiFe 80%NiFe MnZn Ferrite NiZn Ferrite
Core MaterialsPerformance Factor vs. Kilohertz
Soft Ferrite Advantages, Capabilities & Markets Slide 4
MnZn NiZn
Volume Resistivity ρρρρ ΩΩΩΩcm
50 to 100 1x105 to 5x109
Permeability µµµµ 1,000 to 15,000 10 to
1,000 Saturation Flux Density Bm
Gauss 3,000 to 5,000 2,000
to 3,500
Useful frequency Range MHz Up To 10
Up To 100
Density G/cm3 4.8 4.9
Some Important Properties
Soft Ferrite Advantages, Capabilities & Markets Slide 5
Core Loss - A measure of the efficiency of a material at high levels of magnetizing force. Dissipated energy in the form of heat.
Core loss vs. Temperature25kH, 2000 gauss
0102030405060708090
100110120130140
20 40 60 80 100 120
Temperature in Centigrade
mW/cc
TSF-5080 TSF-7070 TSF-8040
• Core size is often constrained by temperature rise that results from core loss
• A number of material grades have been designed so that their minimum core loss occurs at specific Temperatures.
Soft Ferrite Advantages, Capabilities & Markets Slide 6
Saturation Flux Density - The value of magnetic flux density at saturation. A materials maximum magnetic induction.
B = (Erms)(108) / (4.44)(f)(N)(Ae) Saturation Flux Density vs. Temperature
TSF-7070 material15 oersteds
Temperature in Centigrade
Flu
x D
ensi
ty (
gau
ss)
0
1000
2000
3000
4000
5000
6000
-30 -10 10 30 50 70 90 110 130 150 170 190 210 230 250
• Core size is often constrained by Saturation Flux Density • Saturation Flux Density decreases with increasing temperature. Often a material's Saturation Flux Density is a constraint on the minimum core size. f = frequency N= turns Ae = effective core area
Soft Ferrite Advantages, Capabilities & Markets Slide 7
Ferrite Material Constants Specific Heat 0.25 cal / g / °°°°c Thermal Conductivity 10 x 10-3 cal / sec / cm / °°°°c Coefficient of Linear Expansion
8 to 10 x 10-6 / °°°°c
Compressive Strength 60 x 103 lbs / in2 Young’s Modulus 18 x 103 lbs / in2 Hardness (Knoop) 650 Density 4.6 to 4.8 gm / cm3 •••• Ferrites are poor thermal conductors, are strong in compression but weak in tension
Soft Ferrite Advantages, Capabilities & Markets Slide 8
Common Core Configurations
B A
C
B
F E
D
A
C
A
B
F E
D
C
A
B
F E
D
C B
F E
D
A
C
K
Toroid E core ETD core EC core EFD core
A
BC
D
F E
K
C
F EGA
D
B B
D
HFJ
E
AG
C
C HF
B
DG
A
E A HF
B
D
G
C
E
EP core PQ core RM core Pot core DS core
A
B
E
D
C B
F E
D
A
C
D
B
A
C
U core Planar E core Planar I core
Soft Ferrite Advantages, Capabilities & Markets Slide 9
Applications using Ferrites
ν Inductors Inductance is the electrical circuit property that opposes change in current due to a magnetic field
ν Transformers Devices that transform electric energy from one circuit to another by electromagnetic induction
ν Noise Suppression Reduction of unwanted high frequency electrical disturbance
ν Deflection Yokes for CRT & Video Displays Electromagnet for deflecting (directing) electron beams
Soft Ferrite Advantages, Capabilities & Markets Slide 10
Transformer Applications ν Impedance Matching Transformer ν Isolation Transformer ν Current Transformer ν Voltage Transformer ν Wide Band Transformer ν Pulse Transformer ν Switching Power (Output/Inverter) Transformer
ν Flyback Transformer ν Forward Transformer ν Push-Pull Transformer ν Half-Bridge Transformer ν Full-Bridge Transformer
Soft Ferrite Advantages, Capabilities & Markets Slide 11
Soft Ferrite Advantages, Capabilities & Markets Slide 12
Soft Ferrite Advantages, Capabilities & Markets Slide 13
Inductor Applications
νFilter Inductor νCommon Mode Inductor νDifferential Mode Inductor
νPower Inductor νResonant Inductor νBoost Inductor νOutput Choke Inductor
Soft Ferrite Advantages, Capabilities & Markets Slide 14
Inductance - Electrical property that opposes any change in current because of a magnetic field. L = ((.004) (ππππ) (N2) (Ae) (106)) / Le (in Henries)
• Material Permeability, core dimensions & number of turns all affect inductance and therefor affect component size
Ae = effective cross sectional area
Le = effective magnetic path length
N = turns on coil.
Soft Ferrite Advantages, Capabilities & Markets Slide 15
ν Telecommunications Markets
ν System Networks ν Integrated System Digital Networks
(ISDN) ν Modems ν Cell Phones & Pagers
Soft Ferrite Advantages, Capabilities & Markets Slide 16
Power Supply Markets
ν Computers (Notebook to Mainframe) ν Medical Equipment ν Test Equipment
Soft Ferrite Advantages, Capabilities & Markets Slide 17
Fluorescent Lighting Ballast Markets ν Commercial, Industrial & Institutional
Lighting ν Compact Florescent Lamps ν Controllable Lighting ν Emergency Lighting
Soft Ferrite Advantages, Capabilities & Markets Slide 18
Automotive Markets ν HID Head Lamps ν Neon Stop Lights ν Battery Chargers for Electric
Vehicles ν Sensors
Soft Ferrite Advantages, Capabilities & Markets Slide 19
Consumer Electronics
ν Conventional Television ν Digital & High Definition Television ν VCR ν Stereo & Radio