Designing a 90% efficiency 150W power supply with PFC in hours Prepared by Dr. Franki Poon & Dr. Joe Liu PowerELab Limited 1 Designing

Designing a 90% efficiency 150W power supply with PFC in hoursPrepared by Dr. Franki PoonPrepared by Dr. Franki Poon & Dr. Joe Liu& Dr. Joe Liu PowerELab LimitedPowerELab Limited www.powerEsim.comwww.powerEsim.com 11

Designing a 90% efficiency 150W power supply with Designing a 90% efficiency 150W power supply with PFC in hoursPFC in hours


Next 2.5 hoursNext 2.5 hours

• 2:30 – 2:45 Old vs New• 2:45 – 3:15 Active Diode & IC• 3:00 – 3:15 EMI Cancellation & IC• 3:15 – 3:45 Design Methodology – How we trained?

• 3:45 – 4:00 Tea Break• 4:00 – 4:45 Designed by PowerEsim – New design procedure

• 4:45 – 5:00 Q&A


OldOldVSVS

NewNew


OldOld engineer vs engineer vs YoungYoung engineer engineer

20 years ago . . . .

“

For a MOSFET

Conduction loss = 1/3

Switching loss = 2/3 ”

20 years old . . . .

“

For a MOSFET

Conduction loss = 2/3

Switching loss = 1/3 ”


Old Old MOSFETMOSFET VSVS Young Young MOSFETMOSFET

47 ns vs 5 ns, 10 times different


Where is the ZVS ?Where is the ZVS ?

Adaptor – A efficiency demanding product.

How many of them are using ZVS circuit?


Where is the ZVS ?Where is the ZVS ?

Active Clamp 2 Switch Forward

Full Bridge Phase Shift Bridge

Asym. Half-Bridge Half-Bridge


Where is the losses?Where is the losses?

25 %15 %30 % 10 %

Example :

12V@4A

82%

10W loss


Where money can buyWhere money can buy

10 %

• Pay for ZVS

• Pay for lower Rds

• Pay for lower tr, tf . .

• After all, it is only 10%


Where money can’t buyWhere money can’t buy

Band Gap Loss

Copper & Ferrite

Copper Loss


Why not use less copper?Why not use less copper?

• Active EMI Filter

• WT6001 Y-Cap Booster

• Next section

Old New


Why not of not using diode?Why not of not using diode?

• STPS20H100• 0.6V @ 2*7A 100 deg• TO200 package• USD ?? / pcs

• IRF540Z 22m Ohm• 0.54V @ 14A 100 deg• TO200 package• USD ?? / pcs

Old New


If TO220 has the same price . . .If TO220 has the same price . . .

• STPS20H100• 0.6V @ 2*7A 100 deg• TO200 package• USD ?? / pcs

• IPP05CN10 5m Ohm• 0.08V @ 14A 100 deg• TO200 package• USD ?? / pcs

• Active Diode

• WT6002 active diode IC

• Next section


Transformer design calculationTransformer design calculation

• After all those mathematics, how will it perform ?


Mathematics for the lossMathematics for the loss

• Do you calculate it every time on your design stage?


What exactly you are doing?What exactly you are doing?

Np = ?

Ns = ?

Co=?

Do=?

M1=?

Wire =?

Wire=?

• Just simple fill in the blank


Transformer – core and wire onlyTransformer – core and wire only

• PowerEsim – It is not giving parameters for play with design, It is a tool to build the design.


98% VS 99% - 98% VS 99% - not 1% differentnot 1% different

• 98% efficiency• 2% loss• 30W loss

• 99% efficiency• 1% loss• 15W loss

• Efficiency is not just a figure, it does matter.


98% VS 99% - 98% VS 99% - 200% different200% different

• 98% efficiency• 2% loss• 150W converter

• 99% efficiency• 1% loss• 300W converter

• Selling price double by 1% losses cut


What is all aboutWhat is all about

• Active Diode vs Diode – almost same cost.

• EMI IC vs filter – greatly improve efficiency.

• PowerEsim vs Paper design – no cost.


Active Diode

&

EMI IC


EMI solutions: Passive filterEMI solutions: Passive filter

Conventional EMI solutions depend on passive filter using inductors and capacitors:

Inductors: CMC, DMC Capacitors: X-cap, Y-cap

There are limitations when using passive filters: Inductors: Large size and high conduction loss Capacitors: leakage current specifications


Active EMI cancellation IC WT6001:Active EMI cancellation IC WT6001:An effective EMI solution – Y-cap boosterAn effective EMI solution – Y-cap booster

A patented technology developed in PowerELab. An SO-8 IC WT6001 developed with W2.W2. Equivalent to a Y-cap with very large value within the EMI concerned

frequency range only. No boosting effect in the leakage current test concerned frequency

range (50 – 800Hz). Greatly reduce the common mode inductor size and requirements. Reduce converter size and improve conversion efficiency. Provide effective and efficient EMI solution. Built-in electrical surge protection which can easily pass the

EN61000-4-4 and EN61000-4-5 immunity standard.

WT6001


Applications: Replace passive Y-cap Applications: Replace passive Y-cap

LISN

Replaced by Y-cap booster


Effect measurable by oscilloscope when using Y-Effect measurable by oscilloscope when using Y-cap boostercap booster

Noise voltage across Y-cap in switching converter

Noise voltage across Y-cap booster in switching converter

More application examples can be found in the datasheet of WT6001


Practical application examplesPractical application examples

The original EMI filter design cannot pass the EN55022 class B limit.

Filter component:

2 x 20mm high mu toroid for common mode filters 2 x 0.15uF X – cap 1 x 1n Y1-cap connected between primary and secondary


Practical application examples:Practical application examples: Original filter schematic Original filter schematic

C2

L2B

13

24

C1

L1B

13

24

P1

1

P2

1

TH1 F1

• It is a commonly used filter configuration

• L2B is wound with many turns which intends to suppress the low to mid-frequency common mode noise. Its leakage inductance together with C1 also provides differential mode noise filtering

• L1B is a single layer, bi-filer wound common mode choke for high frequency common mode noise filtering


Practical application examples: Practical application examples: EMI measurementEMI measurement

230V pri-sec Y1n U shielded original

EN 55022; Class B Conducted, Average

EN 55022; Class B Conducted, Quasi-Peak

0

10

20

30

40

50

60

70

80

1 10

dBuV

10/3/2005 10:55:40 (Start = 0.15, Stop = 30.00) MHz

DM noiseCM noise

230V pri-sec Y3n3 U shielded original

EN 55022; Class B Conducted, Average


0

10

20

30

40

50

60

70

80

1 10

dBuV

10/3/2005 16:08:11 (Start = 0.15, Stop = 30.00) MHz

Y-cap: From 1n to 3n3Improved but not enough

Failure was identified to be caused by:• Insufficient leakage inductance of the common mode choke for DM noise

attenuation.• The two common mode choke cannot effectively block out the common mode

current.• Further increase of Y-cap can reduce CM noise but fail to meet leakage current

specifications.


Practical application examples:Practical application examples: Solution using Y-cap booster Solution using Y-cap booster

230V CB U shield SDMC SCMC .33uFEN 55022; Class B Conducted, Average


0

10

20

30

40

50

60

70

80

1 10

dBuV

10/3/2005 16:39:55 (Start = 0.15, Stop = 30.00) MHz

Y-cap booster is used to replace the primary to secondary Y-cap

After using the Y-cap booster, L2B is replaced by a small differential mode filter and L1B is reduced to a 9mm toroid with only a few turns to tackle the high frequency common node noise. The test results pass the required limit lines


Practical application examples:Practical application examples: Filter comparison: Before and After... Filter comparison: Before and After...

Failed design even with morecost, loss and bigger size for thefilter

Passed design using Y-cap booster with much smaller filter size that saves cost, power and space


Another practical application examples:Another practical application examples: Filter comparison: Before and After... Filter comparison: Before and After...

Original EMI solution using passive filterin ATX converter

New EMI solution using Y-cap boosterin ATX converter


ConclusionConclusion

Y-cap booster breaks the relationship between the Y-cap values and leakage current requirement.

Greatly reduce product design period and resources.

It can be applied to any position with conventional Y-cap.

Significantly reduce the size and loss of common mode choke implies higher power density and efficiency.

EMI less sensitive to transformer winding capacitance implies more rooms for improving transformer coupling.

Very suitable for equipment required low leakage current like medical equipment.


Active Diode – An easy to use and high efficiency rectifier Active Diode – An easy to use and high efficiency rectifier suitable for all converterssuitable for all converters

Stringent requirements of nowadays converters:

Compact size Low heat generation and high conversion efficiency High output power and output current Low cost ………!!!

Conventional technologies cannot meet the requirements!!


Synchronous rectifierSynchronous rectifier

Use MOSFETs to replace diode rectifiers.

AK 7.8 m9 m0.24 V

AK



MOSFET 0.7W losses @ 10A

SCK 2.8W losses @ 10A

Provides low conduction loss.

Can operate at higher high current without heatsink.

0 2 4 6 8 100

0.5

1

1.5

2

2.5

3

STPS30L30SO8 Active Diode

Losses comparison between SCK and AD

A

W



Usage not limited to converters with high profit margin.

Price of nowadays low RDSon MOSFETs comparable to schottky diodes using the state of the art technology.

Provide even lower converter cost because of reduced heatsink, more output power, higher conversion efficiency…..

Emerge in low cost converter like adaptors, standard open frame converters, ATX …… .



AD

AD

Problematic for some conventional topologies

Special and sometimes complicated driving circuits SR

are needed for different topologies

Performance sensitive to transformer leakage

inductance and operating conditions

Converter cannot be paralleled – Reverse current

Poor efficiency at low load

Limited input voltage range

Simple circuit

Discontinuous mode is allowed

Good low load efficiency

Converter can be paralleled

High conversion efficiency

Works just like a diode


Active diode – Operating principleActive diode – Operating principle

N1 is the current sense winding N2 provides MOSFET driving signals A1 driver circuit (IC WT6002) N1 N3 & D1 form energy recovery

circuit N4 & D2 form reset circuit

AK

N1 N2

N3 N4

D1 D2

A1


Active diode – Operating principleActive diode – Operating principle

Voltage across winding N2 or gate drive voltage Von of SR depends on ratio of N2 to N3

and voltage Vo

Voltage source Vo

can be any voltage source in a converter, e.g. output voltage

3

2N

NVV oon

AK

N1 N2

N3 N4

D1 D2

A1

Toff

Vo

Vo

VN2

VN3

VN4

Von

Ii


Application of Active Diode in different topologiesApplication of Active Diode in different topologies

FlybackFlyback ForwardForward

S

Flyback SR

Co

+

Vin

-

+

Vo

-

S

MagneticReset

Forward SR

FreewheelSR

Lf

Co

+

Vo

-

+

Vin

-



Half Bridge centre tapHalf Bridge centre tap Current DoublerCurrent Doubler

S1

S2

C1

C2

SR1

SR2

Lf

Co

+

Vin

-

+Vo

-

+Vo

-

S1

S2

C1

C2

SR1

SR2

Lf1

Co

Lf2

+

Vin

-



Resonant converterResonant converter

and many others….and many others….

SR1

SR2

Co

+Vo

-ISIN


Successful application of Active Diode in Successful application of Active Diode in converter productsconverter products

AD on 150W ACDC AD on 120W ACDC

AD on 50W ACDC AD on 300W ACDC AD on 60W ACDC AD on 100W DCDC

AD on 1.5 V 200 A ACDC


ConclusionConclusion

A new “Active Diode” technology is presented.

A kind of current driven synchronous rectifier technology that provides high conversion efficiency and eliminates many conventional synchronous rectifier application problems.

Patented technologies.

An Active Diode driver IC WT6002 for easy implementation of the technology.

Well proven by many converter product design.


ReferencesReferences

• Liu, J.C.P.; Poon, F.N.K.; Xuefei Xie; Pong, M.H.; current driven synchronous rectifier with energy recovery sensor Power Electronics and Motion Control Conference, 2000. Proceedings. PIEMC 2000. The Third International , Volume: 1 , 2000, page(s): 375 -380 vol.1

• Xuefei Xie; Liu, J.C.P.L.; Poon, F.N.K.; Man Hay Pong; Current-driven synchronous rectification technique for flyback topology, Power Electronics Specialists Conference, 2001. PESC. 2001 IEEE 32nd Annual , Volume: 1 , 2001, Page(s): 345 -350 vol. 1

• Xuefei Xie; Liu, J.C.P.; Poon, F.N.K.; Man Hay Pong; A novel high frequency current-driven synchronous rectifier for low voltage high current applications, Applied Power Electronics Conference and Exposition, 2001. APEC 2001. Sixteenth Annual IEEE , Volume: 1 , 2001, Page(s): 469 -475 vol.1

• Liu, J.C.P.; Xuefei Xie; Poon, F.N.K.; Pong, B.M.H.; Practical solutions to the design of current-driven synchronous rectifier with energy recovery from current sensing, Applied Power Electronics Conference and Exposition, 2002. APEC 2002. Seventeenth Annual IEEE , Volume: 2 , 2002, Page(s): 878 -884 vol.2

• Xuefei Xie; Joe Chui Pong Liu; Poon, F.N.K.; Man Hay Pong; A novel high frequency current-driven synchronous rectifier applicable to most switching topologies, Power Electronics, IEEE Transactions on , Volume: 16 Issue: 5 , Sep 2001, Page(s): 635 -648

• Xie Xuefei; Liu, J.C.P.; Poon, F.N.K.; Pong, B.M.H.; Two methods to drive synchronous rectifiers during dead time in forward topologies, Applied Power Electronics Conference and Exposition, 2000. APEC 2000. Fifteenth Annual IEEE , Volume: 2 , 2000, Page(s): 993 -999 vol.2

• US patent "Current driven synchronous rectifier with energy recovery" patent number 6,134,131

• US patent “Self-driven synchronous rectifier by retention of gate charge” patent number 6,377,477

• US patent “Current driven synchronous rectifier with energy recovery using hysterisis driver”, patent number 6,597,587


fill in a value

NOT

design a circuit

We are trained to


Fill in values by experience . . .Fill in values by experience . . .Vi=100

Vo=12

Vo=Vi*D*Ns / (1-D)*Np

Vi+Vo*Np/Ns=0.8Vds_max

Vo=Ns*0.3*fs/(1-D)

0.5*Vo_ripple=Q/Co

Vds_max_M1=lowerest cost in stock

Ids_max_M1=lowerest cost in stock

IF_max_Do=2*Io

VR_max_Do=1.2*(Vi*Ns/Np+Vo)

Core_T1=recommended table from ferrite manufacturer

Wire_Np=fully filled

Wire_Ns=fully filled


Then again . . .Then again . . .

• Replace 100pcs of components at bench


Fine, but no need to replace at the bench . . .Fine, but no need to replace at the bench . . .

• Why not replace 100pcs of components at PowerEsim


www.powerEsim.comwww.powerEsim.com

• It’s on-line

• It’s for everyone

• Worldwide access

• 100% server side simulation

• It’s free


Build virtual and real converterBuild virtual and real converter

PFCDeveloped

underInfineon

TDA4863 Evaluation

Design

DC-DCDeveloped

underInfineon

ICE3DS01 Evaluation

Design

150W 90% LCD Converter


160 W PFC – simulation vs measurement160 W PFC – simulation vs measurement

Input Votlage Vs Efficiency %

0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00

100.00

85 110 230 265

160W PFC Input Voltage Vac

Measured

PowerEsim


150 W Flyback – simulated vs measured 150 W Flyback – simulated vs measured

I/P Votlage Vs Efficiency %

0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00

100.00

300 350 405

150W flybackInput Votlage Vdc

Measured

PowerEsim


Loss and Temp.Loss and Temp.


Component Based ApproachComponent Based Approach

• Find MOSFET

• Find Diode

• Find Capacitor

• Find Core

• Find Wire

Rds*Crss

Vf*trrm

CV

k1, k2, k3

Current density

Real components Abstract Concept


PowerEsim vs Traditional DesignPowerEsim vs Traditional Design

result oriented adaptive iteration

instead of

skill of knowledge application

PowerEsim turn design into


But first . . .But first . . .

• Find a circuit that has closest specification to your need, e.g. 160W TDA4863 for PFC front end.


Ask our expertAsk our expert

• Enter the input & output specification

• Chose an application

• Click “Recommend Design”


How our expert system work.How our expert system work.

Specification Search for closest evaluation design

Search for best topologies


If you like more freedomIf you like more freedom

• Click “Topologies”• Chose the topology you like• Enter the input & output specification


Re-define specification Re-define specification

• Click “Detail Spec.”• Change specification

as you like


Click the main MOSFETClick the main MOSFET


How we model component?How we model component?


Click, click, click and selectClick, click, click and select

• A particular one – total & individual loss

• Highlighted one – total, individual loss and stress

• Selected one – total individual loss and stress


Other than loss, Stress is importantOther than loss, Stress is important


More clever method – More clever method – Smart OptimizerSmart Optimizer

Click “Select All”

All MOSFET will dump into a

optimizer pool


Smart Optimizer – just a clickSmart Optimizer – just a click

• Click “Smart Optimizer”

• Enter maximum iterations

• Wait a few seconds


Multi dimensional optimizationMulti dimensional optimization

:

1

2

10

10 resistorx

10 MOSFET

10 diode

x

x:

= 1010 combination

= 31 years simulation


Smart Optimizer – how it workSmart Optimizer – how it work

Data set Smart Scan

Search for good component

Genetic Algorithm

SPD07N60C3BU60

SPN04N60C2

IPP50R520CP

SPB07N60S5

SPD07N60C3BU60

SPN04N60C2

IPP50R520CP

SPB07N60S5


Sorted one by oneSorted one by one

• Result will be ranked• Click to view each result• Optimized Component will be shown


Now Active DiodeNow Active Diode

• Click the diode you like to replace by Active Diode or Sync Rect.

• In the Component Finder, change it’s “Rectifier Type” to

Active Diode


Search more MOSFETSearch more MOSFET

• Extend to higher current range is usually needed

• Extend the body diode’s trrm can

find more MOSFET


Select a better Sync Rect.Select a better Sync Rect.

• 2.54W SCK loss

• 0.5W Active Diode loss


Which component is more critical?Which component is more critical?

• Why M1, D3 & T1

• Loss Analysis – the most useful page

• It rank the loss and it’s details


Follow the stepFollow the step

• Follow the tips from the header is a good practice.

• Just click the box, it will redirect you to other tools

• Go through each box step by step


Click T1 and go to Magnetic BuilderClick T1 and go to Magnetic Builder


Step 1 – select the core you likeStep 1 – select the core you like

• Chose the range of Ae

• Select Core shape

• Select Manufacturer


Instant preview winding when thing changeInstant preview winding when thing change

• Click the “preview winding”

• Corresponding winding cross section will be shown

• Supported on Core, N and Wire.


Step 2 – find the best LmStep 2 – find the best Lm

• Click the “Inductance” button

• Enter the range of inductance

• Highlight each in the list, select according to total loss and stress.

• Double check OCP is not be triggered.


Step 3 – find the best N0Step 3 – find the best N0

• Click the “Number of turn” button

• Enter the range of turn

• Highlight each in the list, select according to total loss and stress.

• Double check OCP is not be triggered.


Don’t forget preview windingDon’t forget preview winding

• Click the “Preview Winding” button

• Observe how winding structure change with number of turn.


Step 4 – need more copper?Step 4 – need more copper?

• Click the “Change Wire” button

• Click the “No. of Parallel Wire”

• Add more parallel wire as you like.


160 W PFC – simulation vs measurement160 W PFC – simulation vs measurement

Input Votlage Vs Efficiency %

0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00

100.00

85 110 230 265

160W PFC Input Voltage Vac

Measured

PowerEsim


150 W Flyback – simulated vs measured 150 W Flyback – simulated vs measured

I/P Votlage Vs Efficiency %

0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00

100.00

300 350 405

150W flybackInput Votlage Vdc

Measured

PowerEsim


DVT – check the stressesDVT – check the stresses

• DVT Report check every components stress and also circuit design constraint.


Thermal – knowing Temp. at day 1Thermal – knowing Temp. at day 1


MTBF – how long it lastMTBF – how long it last


•Live Demonstration

Designing a 90% efficiency 150W power supply Designing a 90% efficiency 150W power supply with PFC in with PFC in minutesminutes

Documents

Designing a 90% efficiency 150W power supply with PFC in hours Prepared by Dr. Franki Poon & Dr. Joe Liu PowerELab Limited 1 Designing