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Zettler Magnetics We know better magnetics

Philip Fung

Standard Transformer Applications

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Property of Zettler M

agnetics

Zettler Magnetics We know better magnetics

General Transformer Glossary• Input Voltage/Current • Output Voltage/Current• Frequency• Topology/Duty Cycle• OCL/Leakage Inductance.• Temperature rise• Ambient Temperature. Ta70B

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Zettler Magnetics We know better magnetics

Safety Related Info.

• Output Voltage LimitEN60950… SELV for 42.4Vpk or 60VDC UL5085… Class II 30Vmax

Class III 30-100V or 150V EN61558-2-6… 50VRMS/120V ripple free DC

• Transformer ClassClass I/II/III in EN60950/EN61558 ProtectionClass I/II/III in UL5085 Voltage

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Property of Zettler M

agnetics

Zettler Magnetics We know better magnetics

Safety related info• Insulation Grade

Class A 105C 100C maxClass E 120C 115C maxClass B 130C 120C maxClass F 155C 140C maxClass H 180C 165C max

TEX-E or Twisted WireMW82 wire and etc….

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Zettler Magnetics We know better magnetics

Creepage and Clearance

6.4mm creepage

3.2mm margin

Secondary

Primaryand clearance

& clearanceOnly 3.2 mm creepage

leadout

8.2mm creepage & clearance

leadout w/ sleeve

5.0 mm3.2 mm

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Property of Zettler M

agnetics

Zettler Magnetics We know better magnetics

Laminated Transformer Types

• Print PCB Transformer• UI Core low profile pin type transformer• Current Sensing Transformer• Lead type transformer• Power everywhere• New edge why still use the laminated

transformer?

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Zettler Magnetics We know better magnetics

Laminated transformer materials • Lamination material

Lamination: Z11, H12, H14, H18, H23, H50

• Standard SizesEI28/30/35/41/48/57/66

• Insulation materialsBobbin (PET, NYLON), TAPE (Polyester), Varnish (C1105, AC43)

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Zettler Magnetics We know better magnetics

Standard Ferrite Magnetics SMPS Application

PFC STAG

E

PFC Choke

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Zettler Magnetics We know better magnetics

Standard Ferrite Magnetics Ballast Application

Differential Mode ChokeOr Common Mode Choke

PFC Choke

Driver Transformer

Main Output Transformer

Sensing Transformer

Property of Zettler M

agnetics

Zettler Magnetics We know better magnetics

Choke Types by Application• Common Mode Choke• Differential Mode Choke• Energy Stock Choke (PFC, BUCK)

Choke Types by Material

• Ferrite Core• Powdered Core (iron, MPP, Sendust)• Laminated Core (EI, taped, Amorphous)

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Zettler Magnetics We know better magnetics

Ferrite XFMR Types by Application• Flyback XFMR (with Gap)• Forward XFMR • PushPull• Full bridge

Ferrite XFMR Types by Shapes• EE 13, EE 16… … • EFD20, • ER28, ETD34…• Planar E40

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Zettler Magnetics We know better magnetics

Ferrite XFMR Material• TDK PC-40• Nicera NC-2H• China Material TDG, DMEGC ……

Ferrite XFMR Bobbins• EE 13, EE 16… … • EFD20, • ER28, ETD34…• Phenolic PM9820 T375J

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Zettler Magnetics We know better magnetics

NO., Supplier Quality(50)Cost(15)

Delivery time(15)

Service(20) Total Grade

1 TDK 48 11 10 17 86 A

2 TDG 47 12 12 18 89 A

3 ACME 47 14 12 19 92 A

4 DMEGC 47 14 14 18 93 A

6 NEC 45 11 12 16 84 B

5 MAGSOURCE 43 14 12 15 84 B

7 GUANDA 40 15 10 14 79 C

Property of Zettler M

agnetics

Zettler Magnetics We know better magneticsItem SymbolConditions Unit NiceraNC-2H

TDKPC47

TDKPC40

TDGTP4

TDGTP4A

DMEGCDRM40

DMEGCDRM44

ACMEP4

ACMEP41

Initial permeability

μiF:10KHzB

Property of Zettler M

agnetics

Zettler Magnetics We know better magnetics

Key Parameters Affect to your power supply• Leakage Inductance

L1

1u

VDrain

TX2

R5

1K

C3330p

R91.8

Q1

IRFR420

X

R81k

R1

100

C6330p

2uH 250V peak spike

20uH 350V Peak Spike

22

21

21 CVLI =

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Zettler Magnetics We know better magnetics

Leakage Inductance

∫a

dxxLo0

2∝cLo ++

3a2a1 ∝

)3

a2a1(*XK cLo ++=

How about Multi-section?

)3

a2a1( ∝ cLo ++

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Zettler Magnetics We know better magnetics

Leakage InductanceThe power to transform

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Key Parameters Affect to your power supply

fDdep 76=

???2DCRXIPcopper =

???* 2IDCRPcopper =

I(t)

H(t)

I(t)

J(t) J(t)

0

Eddy currents

raa

B sin( ωt)

+ -- + - +

+ -

B sin( ωt)

Wire Diameter Skin Effect Copper loss

NO, the SKIN effect caused a Rac

KRdcRac *=

• Mnimize eddy currents using Leitz wire bundle. Each conductor in bundle has a diameter less than a skin depth.

• Twisting of paralleled wires causes effects of

intercepted flux to be canceled out between adjacent twists of the conductors. Hence little if any eddy currents.

IS:2I*K*RdcsPCopperLos =

Not Really, the proximity effect.

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•Mnimize eddy currents using Leitz wire bundle. Each conductor in bundle has a diameter less than a skin depth.

•Twisting of paralleled wires causes effects of intercepted flux to be canceled out between adjacent twists of the conductors. Hence little if any eddy currents.

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Zettler Magnetics We know better magnetics

Proximity Effect

Rac=RdcXFr Famous Dowell Curve

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Gap Fringing Effect

• Fringing cause significant eddy loss

• Avoid the fringing lossby design

• Fringing increases theOCL

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Core Losses

• Core Loss mW/cm^3 or mW/gram• Different loss from different material• Select right materials

Not over design• B vs Core loss

No stress design

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Gap, ue, Bdc

• Bsat inherent characteristics

• Bdc decided by peak current

• OCL decided by turns and gapping size

• Basic formula:1 .10 3 0.01 0.1 1

0

500

1000

1500

2000

2500

3000

3500

4000

4500

µi

µrev ∆B BM,( )

µrev1 ∆B BM,( )

BM

lelgui1

uiue+

=le

NIπ4.0H =

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Powder Core Characteristics• Distribute gap• Soft Saturation• Different powder size

different core loss• Thermal Aging issue• Choose right core

materials

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Common Mode Choke• Impedance

1 .103 1 .104 1 .105 1 .106 1 .107 1 .108 1 .109 1 .10100.1

1

10

100

1 .103

Radians/sec

Ohm

s

943.503

0.895

Z.in 1jωi⋅( )

4.472 109×5.135 103× ωi

L1

1m

• EMI Filtering Network• Mostly are low pass LC

filtering circuit.

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Zettler Magnetics We know better magnetics

EMI Filtering Net Work

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Magnetics Thermal Engineering

• Temperature Rise. Ploss includes copper loss and core loss

833.0)(

=

AsurfmwPlossdT

• Forced Ventilation Effect 0 15 30 45 60 75 90 105 120 135 1500.2

0.29

0.38

0.47

0.56

0.64

0.73

0.82

0.91

1Tempearure rise Vs Air flow

Cubic Feets Minutes

% T

empe

ratu

re

f x( )

x

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Property of Zettler M

agnetics

Zettler Magnetics We know better magnetics

Magnetics IS one of the most important portion in the power supply design

• Thank You for AttendingPhilipFungZETTLER MAGNETICS

[Reference]Leakage Inductance by N.H. Crowhurst 1949Soft Ferrites, Properties and Applications, 2nd Edition 1988 by Snelling E.C.Switching Mode Power supply Handbook by Keith. H. BillingsMicrometals Catalogue Edition 2000Magnetics Calalogue

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Philip Fung� General Transformer Glossary Safety Related Info. Safety related info Creepage and ClearanceLaminated Transformer Types Laminated transformer materials Standard Ferrite Magnetics SMPS Application Standard Ferrite Magnetics Ballast Application Choke Types by ApplicationFerrite XFMR Types by ApplicationFerrite XFMR MaterialSlide Number 13Slide Number 14 Key Parameters Affect to your power supplyLeakage InductanceLeakage InductanceKey Parameters Affect to your power supplyProximity Effect Gap Fringing EffectCore LossesGap, ue, BdcPowder Core CharacteristicsCommon Mode Choke EMI Filtering Net WorkMagnetics Thermal EngineeringMagnetics IS one of the most important portion in the power supply design