System Power Design for Wall-Powered Application Instruments System Power Design for Wall-Powered Application Dec, 18 th-22, 2006 Kevin Lin HPA Asia Market Development

Texas InstrumentsTexas Instruments

System Power Design for Wall-Powered Application

Dec, 18th - 22th, 2006Kevin Lin

HPA Asia Market Development

2

Utility AC LineUtility AC Line--Powered SystemsPowered Systems

Portfolio Strength in...Portfolio Strength in...AC/DC, isolated DC/DC Power factor correctionPoint-of-load DC/DCPlug-in power modulesHot swap/PoEPower distributionFET gate driveDigital power

Full System Solutions

IndustrialIndustrial

CommunicationCommunication

ComputingComputing

ConsumerConsumer

3

Texas Instruments Power HistoryTexas Instruments Power History

TI has Built the leading Power Management Business

ContentContent

ACAC--DC PFC DC PFC IntroductionIntroduction & Design Considerations& Design Considerations

Isolated PWM SolutionsIsolated PWM Solutions IntroductionIntroduction

DCDC--DC Buck DC Buck Design Software IntroductionDesign Software Introduction

5

What is What is Power Factor Correction Power Factor Correction ??

Line Voltage - Vin

Line Current - Iin

Without Active PFC (PF= 0.55)

Non-linear Load

Line Voltage - Vin

Line Current - Iin

Without Active PFC (PF= 0.80)

Linear Load

)cos(PFnt Displaceme φ=

total

1

IIPF Distortion =

THD+=

1)cos(PF φ

PowerApparent Power RealFactorPower =

6

Benefits for PBenefits for PFCFC CircuitsCircuits

Power Factor Correction is Widely Used

Increases Current Available from LineReduces 3rd Harmonic DistortionEuropean Market Requirement

• EN 61000-3-2 is following standard

Enables Universal Line Operation w/o Mech-Switches• No need for switches to handle 120V vs... 240V line voltage

Easier to Meet Hold-up Time Requirements• Energy is stored at a higher voltage of bulk capacitor

Can make Second Stage Design Easier

Line Voltage - Vin

Line Current - Iin

Without Active PFC (PF= 0.55)

With Active PFC (PF= 1.0)

Look at Available System Power:Assume 15A Breaker, 98% η Rectifier, PF=0.55 (Typical Rectifier w/o PFC)

P = 120 Vrms • 15 A • 0.55 • 0.98 = 970 WIf PF = 0.99 Available Power = 1746 W

Increases “Available” Line Power of 80%

7

Power Factor CorrectionPower Factor Correction

Simple StructureNo RegulationLarge HarmonicsLow Power Factor

Vi

Relative ComplexRegulated OutputLow HarmonicsHigh Power Factor

Vi

8

Vin -+ -

+

D)-(11VV);VV(V

)VV(D)1(VDV;TstD

inoutLinout

inoutinLon

×=+=

−×−=×==

Boost Topology for PFCBoost Topology for PFC

t(a) CCM

t(b) CRM

Diode Current

Switch Current

Diode CurrentSwitch Current

IL_pk_ccm

IL_valley_ccm

C

VOUTL

Q1

IL ID

IQ

IL_pk_crm

Most Popular TopologyVout > Vin Ideal for Universal Line Inductor Current = Input CurrentMany Control ICs Available

9

PFC Design ConsiderationsPFC Design Considerations

Trade-Off in between Performance and Total System Cost Optimum control method – Average Current Mode (ACM) Simpler inexpensive control – Transition Mode or Critical Mode (DCM)High-efficiency & performance – Zero Voltage Transition Mode (ZVT)

To Meet System Operation RequirementHigher PF and lower THD features – input current harmonics shall comply with IEC 61000-3-2.PFC bulk capacitor design – hold up time; Iripple & voltage ratingAppropriate DC filtering capacitor – bypass current ripple noisePower sequencing techniques for PFC & PWM stagesSafety and EMI requirements (conduction & radiation)

System-Board Space & Development Time LimitationLayout & placement issue – guideline Thermal dissipation management

Stability and ReliabilityProtection features (OVP, SCP, UVP, OCP, OTP)

10

Transition Mode (TM/ DCM) PFCTransition Mode (TM/ DCM) PFC

Constant On Time ControlNo Reverse Recovery Current on Boost DiodeMOSFET ZVS Turn On is PossibleSmaller Inductor ValueVariable Switching FrequencyLarge Ripple Current Requires Larger Input FilterHigh Current Stress and High Conduction Loss on MOSFET

ton

11

TM PFC Operation PrincipleTM PFC Operation Principle

0

IL

In each Switching Cycle onin

pkavg tL

VII21

21

==

Input Voltage is Sinusoidal, Inductor Average Current is also Sinusoidal if Ton is Constant

ton

Ipk

12

Switching Performance EstimationSwitching Performance Estimation

Because of Resonance between Boost Inductor and MOSFET Junction Capacitor, Less Turn on Loss can be Realized

ZVS can be Achieved if Input Voltage is Less than Half of the Output Voltage

Less Turn On Loss is Expected Comparing with CCM Mode

IL

Vds

Because of Transition Mode Operation, No Reverse Recovery LossLow cost, Standard Diode can be Used

Vds

IL

13

+–

R IMO

GATEDRIVE

+–

C O

LOAD

R I

R FC Z

C P

TEXT+–

IMPROVEDNOISE

IMMUNITY

PWMV S

Q1

IMO

V INI IN

IINR SENSE

– +

ACLINE

IAC

LPF

MULTK M

SQUAREK G

DIVK D

E/A

E/AN

D

V VAV REF

L IN

ID1 V O IO

V O

V FF

D1

Real Current Waveform

Input Voltage Sine Waveform

Input Feed Forward

Output Bus Voltage

Current Follow & Commend

Regulation & Constant Power

PWM Commend

UCC3818A UCC3818A -- 16 Pin CCM PFC Controller16 Pin CCM PFC Controller

Real Current Waveform

Input Voltage Sine Waveform

Input Feed Forward

Output Bus Voltage

Current Follow & Commend

Regulation & Constant Power

PWM Command

14

Average Current vs. TM Mode Average Current vs. TM Mode

Smaller Ripple CurrentSmaller RMS CurrentSmaller EMI FilterConstant Switching FrequencySuitable for High Power LevelLarge Switching Loss because of

Diode Reverse Recovery CurrentHigh Cost Components to Maintain

High Efficiency

No Reverse Recovery LossLow Cost SolutionSoft Switching PossibleLarge Current Ripple, Increasing

Conduction Loss and Switching LossLarge EMI FilterVariable Switching FrequencyNormally Limited to Low Power

Level

15

LCD-TV Power BoardAC-DC Open Frame PowerMid to High Power AC Adapters

• Slew Rate Comparator for Improved Transient Response

• Zero Power Detect to Prevent Over Voltage Conditions under Light Load

• Over Voltage Protection• Open Feedback Protection and Enable Circuits• Low Startup & Operating Current• 750mA Source/ Sink Peak Gate Drive to Reduce

Switching Losses• UCC38051 Implements Lower UVLO Start-up Voltage

for Compatibility (Typical application: AC Adapters)• SOIC/ PDIP Package

EVM and SampleES: NowRTP: Now

UCUCCC28051 28051 -- Transition Mode PFC ControllerTransition Mode PFC Controller

Slew Rate Comparator

Over Voltage ProtectionLine Voltage Follow

Open Feedback Loop Protection

750mA Source/Sink

ZCS Detection

16

UCUC22853853AA -- 8 Pin CCM (ACM) PFC Controller8 Pin CCM (ACM) PFC Controller

ATX PC PowerLCD-TV and PDP-TVHi-Power Adapters

• Complete 8-pin Power Factor SolutionReduced External Components

• 500mA Source/ Sink Peak Gate Drive toReduce Switching Losses

• Traditional Multiplier Line Voltage Compensation

• Internal 63KHz Synchronizable Oscillator• Average Current Mode Control with

Improved Noise Immunity• Over Voltage Protection Comparator• 8-pin PDIP (P) and (SOIC) (D) packages

Internal 63KHz Oscillator Over Voltage Protection

Traditional Multiplier Line Voltage Follow

Average Current Mode 500mA Source/Sink

Maximum Vcc: 40V

EVM and SampleES: NowRTP: Now

17

UCC28510UCC28510 --17 PFC/ PWM Comb17 PFC/ PWM Comboo ControllersControllers

12

3

16

18

10

5

7

2

UCC2851X

GT1

VSENSE

ISENSE1

IAC

GT2

VREF

VERR

RT

+–

D1

VAC

15

14

13

11

17

19

20

PWRGND

VAOUT 1

6

VFF

MOUT

CAOUT

PKLMT

SS2 8

9

D_MAX

CT_BUFF

GND

ISENSE2

VCC

REF

PRIMARY SECONDARY+

-VOUT

+4

REF

BIAS

RECT

+

-

PWMV-LOOP

Z

ZZ

End Applications:• Desktop and Server Computer Power Converters

• Distribution Power System Front Ends

Feature BenefitPFC & PWM Stages

Trailing Edge/Leading Edge Modulation

Minimize Ripple Current in Boost Capacitor

3A Sink / 2A Source Gate Drives

MOSFET Switching Efficiency

TransconductanceAmplifier

Enhanced Transient Response

Multiple UVLO Options Optimizes Start-up and Turn-off behaviors for Differing Biasing Schemes and Load Transient Requirements

PFC Stage

Improved Multiplier Improved Power Factor and THD

Programmable Max Duty Cycle

Protects Downstream Power Stage

1x:2x PFC:PWM Frequency Flexibility for Different PWM Topologies

PWM Stage

Combined PFC and PWM Power Stages in One Chip

Built-In Sequencing for Reduced complexity and Cost

18

Power Factor Correction ControllersPower Factor Correction Controllers

Avg. I-Mode

Transition Mode

ZVT

Specialized PFC Controllers

Zero Voltage Switching PFC (Telecom Rectifiers, >1kW High Power)

PFC+PWM Combination Controllers (Desktops, Flyback, Boost)

General Purpose Average Current Mode CCM PFC

Transition Mode or Boundary Mode (Adapters, Lighting Ballasts)

UCC28050/51Improved Transient

Resp., Industry Std. Pinout

UC2853A8-pin CCM<65KHZ

UC3855A/BZVT, Higher Frequency

UCC38500-03PFC+PWM, LEM/TEM

UCC28510-17PFC+PWM, LEM/TEM,

Prog.MaxDC

UCC3819/ATracking

Boost PFC

UCC3817/18; UCC3817A/18A

BiCMOS UC3854A, LEM

UCC28018/198-pin CCM

PFC

UCC28018/198-pin CCM

PFCUC3854A/BImproved

16-pin CCM

Existing Products 2007+

UCC28070Interleaved CCM PFC

UCC28070Interleaved CCM PFC

UCC28060Interleaved TM

PFC

UCC28060Interleaved TM

PFC

UCC28521UCC28528PFC+PWM, TEM/TEM,

Prog.MaxDC

19

ACAC--DC PFC DC PFC IntroductionIntroduction & Design Considerations& Design Considerations

Isolated PWM Solutions IntroductionIsolated PWM Solutions Introduction

DCDC--DC Buck Design Software IntroductionDC Buck Design Software Introduction

20

Isolated PWM Solutions by Topologies (1)Isolated PWM Solutions by Topologies (1)

21

Isolated PWM Solutions by Topologies (2)Isolated PWM Solutions by Topologies (2)

22

Topology Power Level Benefits Drawbacks Cost

Flyback <120 WLow parts countSingle magneticWide input-voltage rangeLow output power

Poor efficiency at high power levelsHigh peak currentsCross regulation problemsHigh-voltage power switch

Lowest

1 Switch Forward

150 Wto

350 W

Medium output powerGood cross regulation with coupled inductorPotential for >50% duty-cycle

Limited input rangePower switch = 2 VINTransformer reset

Moderate

2 Switch Forward

400 Wto

800 W

Medium output powerPower switch = VINCoupled inductorClamped transformer reset

Limited input rangeHigh-side drive circuit required50% duty-cycle limitLarger inductor value

Moderate

Half-Bridge300 W

to600 W

Medium output powerPower switch = VINCoupled inductorMax duty-cycle < 100%

Limited input rangeHigh-side driveVolt-second balance of transformerCenter-tapped secondary

Moderate

Push-Pull50 W

to300 W

Good core utilizationCoupled inductorBoth switches ground referencedSmall output inductorMax duty-cycle < 100%

Power switch = 2 VINLimited input rangeCenter-tapped primary Volt-second balance

Moderate

Full Bridge >800 W

Resonant switching can improve efficiencyPower switch = VINCoupled inductor Very high output powerMax duty-cycle < 100%Efficient transformer design

4-power switchesTop FET driveVolt-second balance

High

Analysis of Isolated PWM TopologiesAnalysis of Isolated PWM Topologies

23

Switching frequency delay turn-on until both Fsmax and VDS turn-on when resonates to minimum voltage and IDS = 0

Switching frequency clamps variable within a range of 40 kHz to 130 kHz at maximum for higher line and/or lighter load conditions

Turn-off by peak current PWM control

IMAG

IPRI

t

t

t

VDS

t

VIN

ISEC

t

∼ LMAG CDS

Leakage Inductance energy

VGS

N x VO

CDSGATEDRIVE

IS

IP VDS

+VIN-

VO

QuasiQuasi--Resonant Operation for Valley SwitchingResonant Operation for Valley Switching

+-

-+ -

++-

Flyback Conversion

24

UCC28600 UCC28600 -- QR Green Mode ControllerQR Green Mode Controller

Full Green Mode Capability in 8-Pins; Multi-Mode Operation Provides Advanced Energy Saving CapabilityLow Standby Current for System No-Load Power Consumption to 150mWLow Frequency (40KHz); Burst Mode for Better Efficiencies at No-Load Operation Programmable Over Voltage Protection, Line and Load; Over-Current Hiccup Restart ModeGreen Mode STATUS Pin Disables PFC Function during Light Load for Energy Savings (Can Disable PFC)+1ATrueDrive Gate Drive Output

Green Mode STATUS Pin for PFC Disable

Over Voltage Protection

Quasi-Resonant Mode Operation

Low Standby Current; No-Load Power Consumption to 150mW

+1A Sink/ 0.75A Source Gate Drive

ZCS Detection

PinlessDemagnetizing Sense Circuit

Soft Start Programmable

Current Feedback

Bias Supplies for LCD-Monitors, LCD-TV, PDP-TV, Set Top Boxes

AC/DC Adapters & Off-line Battery ChargersEnergy efficient power supplies up to 200W

ES: NowRTP: Now

25

Applicable to Forward and Flyback TopologiesActive Clamp Applied to Either High Side or Low Side

Advantages– Natural ZVS (Zero Voltage Switching) for Highest Efficiency– >50% Duty Cycle– Recycles Inductive Energy– Reduced EMI– Easy to Adapt Self-Driven Synchronous Rectification

Disadvantages– Additional MOSFET Switch Required for Active Reset– Gate Drive Circuitry somewhat Complex– Precision Max Duty Cycle Clamp is Critical– Advanced PWM Control Technique Required

Benefits of Active Clamp TopologyBenefits of Active Clamp TopologyLossless Transformer Reset

- Magnetizing energy can be recycled - Higher efficiency

Higher Max Duty Cycle - Possible to go beyond 50% duty cycle that reduces

average switching current- Wider input voltage range and higher turn ratio- Current stresses on the primary side and voltage

stresses on the sec side can be reduced significantly

Switch Voltage is Clamped to Control Level, Resulting in Lower Stress Switching Device

ZVS of the Main Switching is Possible, Leading to- Lower switching losses - Higher frequency operation- Lower EMI/RFI

Transformer Waveform Allows for Easy Implementation of Sync-Rectification on the Secondary Side.

26

Active Clamp Reset TechniqueActive Clamp Reset Technique

(a)(a)

(c)(c)

(b)(b)

(d)(d)

27

Why there is no ZVS when Main Switch turnsWhy there is no ZVS when Main Switch turns--on ?on ?

If the secondary side leakage is small the magnetizing energy necessary to turn D1 on will be diverted through D3 (Q3) during the reverse recovery of D4 (or Q4 reverse conduction)

After the reverse recovery of D4, the magnetizing energy will continue discharging through the loop shown in blue

Since there is no energy to turn D1 ON, ZVS of Q1 does not take place.

28

UCC2891/2/3/4/7 UCC2891/2/3/4/7 –– Active Clamp ControllersActive Clamp Controllers

Product ControlGate Drive

(Sink/Source)

HV Startup Circuit

SYNCLINE

MonitorAuxiliary

Output

CS1 Thres-hold

CS2 Thres-hold

Slope Comp

Max. Osc. Freq.

UCC2891 CMC±2A

TrueDrive™

(110V) (UV)P-Ch 0.75V - 1MHz

UCC2892 CMC±2A

TrueDrive™ - (UV,OV)

P-Ch 1.27V - 1MHz

UCC2893 CMC±2A

TrueDrive™

(110V) (UV)N-Ch 0.75V - 1MHz

UCC2894 CMC±2A

TrueDrive™ - (UV,OV)

N-Ch 1.27V - 1MHz

UCC2897 CMC±2A

TrueDrive™

(110V)

(Bi-dir)

(UV,OV) P-Ch 0.5V 0.75V 1MHz

UCC3580 VMC +1A / -0.5A - - P-Ch or N-Ch

- - N/A 400kHz

Performance / Efficiency:– ±2-A TrueDrive™ Gate

Drives

Flexibility:– Telecom bus compatible

Built-in 110V Start-up Circuit

– Prog. Internal Slope Comp– Bidirectional Oscillator

Synchronization– -40°C to +125°C Operation

Protection:– Incorporates 0.5V Cycle by

Cycle Current Limit – 0.75V Second Level Hiccup

Mode Threshold– Accurate Input Line UV and

OV Protection Monitors

29

PWM Controllers (50W PWM Controllers (50W ––>1KW)>1KW)

Existing Products 2006+

Soft-Switching, ZVT, ZVS (Phase-Shifted Full-Bridge, Resonant, Active-Clamp Forward)

Dual- Complementary Outputs (Push-Pull, Half-Bridge, Full Bridge, Current-Fed/Voltage-Fed Push-Pull, Two Independent Flybacks/Forwards)

General Purpose Single Ended PWM(Forward, Flyback, Buck, Boost, SEPIC, Cuk)

Secondary Side Control; Post Regulation(Forward, Buck, Synchronous Buck)

Green-Mode PWM and Off-line Bias Regulators(Flyback, Forward, QR Flyback)

UCC3580V-Mode

Act-Clamp

UC3861-8Resonant Mode

Controllers

UCC3895Adv. Φ-Shift

UC3875-8w/ Drivers

UC3879w/o Drivers

UC3524AUC3525AUC3526A

UC3846UC3856

UC3825A/B

UC3825

UCC3806

UCC3808/A8-pin P-P

UCC38083-6+Slope CompUC28025

UCC28220/1Interleaved

Fwd/FlybackProg MaxDC >50%

UC3849Avg.I-Mode

w/ LS

UC3824UCC3839

Avg.I-Mode

UCC3960/61Primary Side

Start-up

UC3827I/V-Fed P-P

UCC2891-4I-Mode Act-

Clamp, HVStart

UCC3580SR Control

UCC3583UC3854SSPR

UCC38102 Independent

Channels, ≤50%DC

UCC2541Sec. Side Sync-Buck

w/ Osc., PGD™

UCC2541Sec. Side Sync-Buck

w/ Osc., PGD™

UCC2897Adv. I-Mode Act-Clamp,

HVStart

UCC2540Sec. Side Sync-

Buck, PGD™

UC3827I/V-Fed P-P

UCC28089Push-Pull Osc

UC3842-5UC3842A-5A

UCC3800-5UCC3813

4/5Vref, SS, LEB

UCC3884Freq. Foldback,

V*S ClampUCC38C42-45

BiCMOS 3842A-45A

UCC3807UCC3809

Prog. Max DC

UCC3888/89Off-line BiasRegulators

UCC28600QR Green Mode PWM

UCC28600QR Green Mode PWMUCC3581

Micro PowerGreen PWM

Voltage Mode

Current Mode

Resonant Mode

ACAC--DC PFC DC PFC IntroductionIntroduction & Design Considerations& Design Considerations

Isolated PWM Solutions IntroductionIsolated PWM Solutions Introduction

DCDC--DC Buck Design Software IntroductionDC Buck Design Software Introduction

31

TPS5430/31 TPS5430/31 -- HighHigh--VinVin NonNon--Sync. ConverterSync. Converter

Consumer: LCD-TV, PDP-TV, P-DVD Player, Car-TV, IP-STB, Video Phone Industrial: Point-of-Load Regulation for 3.3/5V LogicTelecom CPE Side and AutomotivePower Supplies

• 5.5~36V (5.5~23V) Input Range; 8pin Power Pad SOIC• Integrated 110mΩ Rds(on) High Side Switch for 3A

Continuous Output Current• Adjustable Output Voltages down to 1.22V with 1.5%

Accuracy• Internal Compensation Allows Lower External Part Count• Internal Slow-start, Under-voltage Lockout, Current limit,

Thermal shutdown and Enable

Enable ON/OFF Control

110mΩ Rds(on) Continuous 3A Output5.5V~36V (5.5~23V) Input Voltage Range

Internal Compensation & Slow Start

Down to 1.22V & Reference with 1.5% Accuracy

Switching Frequency Fsw: 500KHz

Voltage Feed Forward Internal Bootstrap Diode

32

Design Tool (Software) IntroductionDesign Tool (Software) Introduction

Designer Software Tool:

TI Web TI Web –– power.ti.compower.ti.comDesign Software Includes:

Completed Circuitry, Components Value and DatabasePower Specification & Key Parts Stress AnalysisLoop Response & System Stability AnalysisEfficiency Curve & Bill of MaterialPCB & Power PAD Layout Guideline

SWIFT Design Software

TPS40K Design Software

33

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