Overview of Some Power Management Issues - BGUpedesign/slides/Presentation2008.pdfzDC-DC PowerconverterDC Power converter zDC-AC Inverter zAC-AC Cycloconverter Prof. S. Ben-Yaakov,

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Prof. S. Ben-Yaakov, Overview [1]

Overview of Some Power Management Issues

Prof. Shmuel (Sam) [email protected]; 08-6461561; 054-4841947


OUTLINE

• Power conversion principles• Conversion types: dc-dc, ac-dc, dc-ac• Typical areas of applicationTypical areas of application• Devices: switches, drivers, controllers, supervisory • Analog versus digital control


Power Conversion Objective

PowerConversion

ElectricityType A

ElectricityType B

Uniderectional Power

OrBidirectional

Needed in all modern systemsExcept: incandescent lamps, heaters…

2


Conversion Typesby Functionality

AC-DC RectifierDC-DC Power converterDC DC Power converterDC-AC InverterAC-AC Cycloconverter


Types of power Convertersby Technology

Linear power converters

Switch mode power converters– Switched inductor– Switched capacitor


LINEAR REGULATORS

Why not Linear ?

3


Linear Regulator

Vin Ro

IB

VoI1 I2

I II1 ≈ I2Power lost depends on voltage drop on regulatorRegulator needs a minimum of 3 volts (Low Drop Regulators (LDO) ~min(Vin-Vo)=1V or lessBut: Vin-Vo Variations ~3V


Io

Io

VoRs

RLVin+-

Linear Power Conversion Systems

o

RsRso

o

in

o

oin

oo

in

o

VV1

1VV

VVV

IVIV

PP

+=

+==

⋅⋅

==η

o

Rs

o

Rs

VV

PowerOutputLostPower

PP

==


Example

W100P;1V5V5

PP

losso

loss =→==

100W, 5V power supply

Assume: V3)VV( alminnooin ≈− V5)VV( maxoin ≅−

o

%50100200100% ≈⋅=η

%50% =ηThe problem is not It is 100W !

• Battery → efficiency• Line operation → heat dissipation• Cooling → size, expense

4


Switched Mode Converters

High efficiencySmall size

Source

L

CS

R

LoadSource Load

L, C: Reactive elementsS: “On” Resistance →0

“Off” Resistance →∞Low Losses→

⎭⎬⎫


Switched Inductor ConvertersThe Most popular approachCharging and discharging and inductor

inV oC oR outVLin o

inV oC oR outV

LI

L

LI

Charging

Discharging


Implementation

1Q

LinV

1D Q

2D

C R

outV

LinV

12Q

L

1D

2D

C R

outVON OFF

5


Dual Buck + LDO Regulator(FPGA and CPLD Application)


Inside the TPS75003


Inside the TPS75003 - LDO

6


Offline converter

Higher level of integration


Disadvantagesof switch mode converters

More Expensive (in general, when comparable)NoisyLess ReliableSwitching Losses

500kHz

Switchingfrequency

Powerlevel

102W 104W 106W

100kHz

1kHz

Size

Switchingfrequency

200 kHz


Parasitic losses– Conduction– Leakage

Switched Inductor Conversion Systems: Sources of Losses

– ESR

Magnetic (core) losses

Switching losses– Transistor switching – Diode reverse-recovery

7


controlGSV

SV SVI

t

Switching lossesHard Switching

SI

dJswitchingP

t

t

Switching losses due to overlap Pd linear with fS !


Soft Switching Real and pseudo

DVDI

dtdVD

DV

t

snubberdtdV

switchingsoft"True"

switchingsoft"Pseudo"

snubberdtdI


Forward with Active Clamp

8


Asymmetrical Half BridgeSynchronous Rectification

SOFT SWITCHING


Micrel 8Mhz Converter

Tiny inductor: 0.5 uH


Micrel 8Mhz Converter with Standby LDO

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Micrel 8Mhz Converter - Performance


Reverse current at switch turn on

Vin

L

C R

Vx Vo

Diode Reverse Recovery


Switched Capacitor ConvertersUsing capacitors as switching storage

inV oC oRC outV

Voltage polarity inverter (negative supply)

inV oC oRC outV

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Calculation the energy lost when C is switched from V1 to V2

V1 V2C

;2

CVE21

1 = ;CVQ 11 = ;2

CVE22

2 = ;CVQ 22 =

);VV(2CEEE 2

22121C −=−=Δ

;CVCVQ 21−=Δ);VV(CQ 21−=Δ

( )( );2

VVVVCE 1221C

+−=Δ 2212V )VVC(VVQE

2−=⋅Δ=Δ

⎥⎦⎤

⎢⎣⎡ −+−=Δ−Δ 2

1221VC V

2VV)VV(CEE

2

[ ]2

VC2

VVVVCEE2

2121VC 2

Δ⋅−=

−−=Δ−Δ

Energy Lost


Implications:

LV Co Ro

Switched inductor

“Lossless” process

CCo RoV

Switched capacitor

“Lossy” process


Analog CaseLossless Switching Lossy switching

21 VV ≠

V1 V2V1 V2

I1 I2

IV

I2I1I1 I2

CI

dtdV =

21 II ≠

21 VV ≠ICVC

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Switched Capacitor Converter


Switched Capacitor Converter


Packaging for Power Dissipation

12


Catalyst’s LED Driver


Catalyst’s LED Driver -Efficiency


Typical areas of application of Switched Mode PS (Buzzwords)

Off line - power factor, isolation, chargersTelecom - modular, PFC, intermediatebus cablebus, cableAutomotive Power over internet – PoEAuxiliary power supplyPortables - low voltage, single cell, chargers

13


Typical areas of application of Switched Mode PS (Buzzwords)

Cont.

Lighting- ballasts, fluorescent, HID, LEDMotor-drive – inverter AC high voltageMotor-drive – inverter, AC, high voltage PC/Servers – VRM, VRDDistributed DC-DC – POLAlternative energy – Solar, wind, fuel cellsSupervisory


Off Line


Digital CameraOld Design

Dig_Cam_Marked.pdf

14


Maxim’s ASIC Solution

Maxim.pdf


Freescale –Recent Product (Smart Mos)


Devices: switches, drivers, controllers, supervisory

Power elementsPower elements Peripheral elements

15


Power Switches

BJT MOSFET IGBT

G

C

E

G

D

S

CB

E

BJT MOSFET IGBT

G

C

E

G

D

S

NPN

C

B

E


Relatively slow (storage time)

Replaced by MOSFET or IGBT

BJT Drive problems

Still is use in lamp ballasts and in very high power applications (motor drive)


Gate voltageNormal : 15V -15V

Power MOSFETs

n channel Internal diodes

p channel

Normal : 15V 15VLogic level: 5V -5V

n channel more popularless expensive

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MOSFET → Rds(on) BJT, IGBT → VCE (sat)

Pd(MOSFET) →(I )2 Rds(on)

Characteristics of Active Switches

Pd(MOSFET) →(Irms) Rds(on) Pd( BJT, IGBT) → Iav VCE (sat)

SpeedMOSFET > IGBT > BJT

High Power → IGBT


Other Switches

SCR - low frequency no forced turn off

MCT - SCR+FET input

GTO turn on and off; slow high currentGTO - turn on and off; slow, high current


Cgs

CgdIg CdsRg

Vs

Driver Requirements

Q

Vgs

Vt

Qgs+Qgd

Qgs+Qgd

Miller capacitance15V

Q1 Q2 Q3

Capacitors are non-linear

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t

VS

Vgs

15VDL

C RL

VoVin

RgIg

Driver Currents

t

t

Ig

VS Vgs


Gate Drivers

High current into capacitive loadHi h lt 15V t i lHigh voltage - 15V typicalFast – tr 100nS and less Logic level inputHigh side


BJT Driver (TI –Unitrode)

Totem pole

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MOSFET Gate DriverMicrel


TI BiCMOS Driver


Driver Interfaces

19


High-Side Drive

The problem Solution #2 :Transformer couplingVb

G tRs

Problem1.Wide range of Don

VGS

Gatedriver


Solution #2: Optical

VC - floating supplyDriver

VC

High-Side Drive – Cont.

Solution #3:Voltage offset

VC floating supply

Driver+VC

Re


Voltage offset + floating C supply

D i

CRg

Re

Available for HB, FB

Driver

Internalcircuit

in+15V

20


HB High Voltage Driver (IR)

600V



The Analog Controller Approach

21


Analog Controllers

Generating PWM signal Error amplifier DriverDriver


Typical Analog Controller


IC Converters

22


Embedded Power Switches Challenge

Linear analog plus switchesSingle versus multi-chipHVHV Obvious advantages to one package


Efficiency


CONTROL

Stabilizes and/or shapes the output signalStability and dynamics issuesAnalog and Digital control

23


Analog Controller

1R1CfR fC

outV

2ReV

PWMrefV

.Amp.Op


VV

CompeV

rampV

PWM

Analog PWM Generator

rampVeV

t

t

V

PWM

SS f

1T =


Analog ApproachPros– Low cost– Trivial to design– Fast– Parallel computation

E t i l t C t M d– Easy to implement Current Mode control

Cons– Many components– Analog– Difficult to change– Large PCB area

24


The Digital Approach


Digital Control

1R

outV

]V)1n(V[a)1n(d)n(d refo1 −−+−=

1R

2RDPWM D/Amachinestate

orogramPrD

High sampling rate – high resolution


Digital PWM (DPWM)

CounterogrammablePr

n

clk

PWM

Comparator

gisterReDRatioDutyn

nS

S f1T =

PWM

25


frequencyswitchingfS −frequencyclockhigestfCLK −

%resolutionPWMsRe −

%100fsRe S=

DPWM Requirements

%100f

sReCLK

=

)bit10(%1.0sRekHz400f:Example

S

==

MHz40010104f

100sRe

ff

35CLK

SCLK

=⋅⋅=

=


The Digital ApproachPros– Programmable– Stable– Potentially of small PCB size

ConsCons

– Expensive because:Needs very fast A/DHigh clock frequency for PWM resolutionDigital control requires higher bandwidthHeavy computation requires DSPComplex to designDifficult to implement Current Mode Control


Requires new DPWM concepts

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Performance of new DPWM


Traditional Analog Power Supply (TI)

OutputV PFCFilter Bridge VV V

8 4

5 1

DC/DCC

Current/LoadSh i

DC/DC V

PFC C t lInrush/

H t l

I I I I

PFC C t lInrush/

H t l DC/DC

C tCurrent/Load

Sh i

UCD9K: System Simplification, Programmability in a Telecom Rectifier

•Multiple chips for control•Micro-controller for supervisory•Dedicated design

Aux P/S

ConverterControl

Multi-modePower control

MCU SupervisoryHousekeeping

Circuits

SharingControl

To Host

PFC Control

InterfaceCircuitMonitor(MCU?)

Hot-plug Control

PFC Control

InterfaceCircuitMonitor(MCU?)

Hot-plug Control

ConverterControl

Multi-modePower control

MCU SupervisoryHousekeeping

Circuits

SharingControl


Digital Power Supply (TI)PFCFilter

BridgeVV

8 4

5 1

DC/DCI

Output

Aux P/S

Eliminate Components

Better Performance Across Corners

Failure Prediction

Reduce Manufacturing Cost

One Design, Multiple Supplies

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What is UCD9501


Comparing Analog to DigitalCurrent Mode Control Example

D

1R

2R

oCQFF

L

OSC S

R

inVoutV

2SR

COMPfR fC

.Amp.Op

3R

refV

Cycle-by-Cycle protectionGood dynamics


TI “Digital” Solution

28


TI’s Nixed Mode Solution


iWatt


Zilker Labs

29


Zilker Schematics


Silicon Labs


Silicon Lab

30


Systel


Primerion


Intersil - Primerion

31


Intersil - Primerion


Volterra


Volterra

32


Volterra


Volterra


Power One

33


Potentia


Potentia


Summit Microelectronics

SMB112- Five-Channel Digitally Programmable White LED and TFT-LCD Power Manager

34


Summit MicroelectronicsThe Details

SMB112EV.pdf


Summit Microelectronics


IR Multi-Phase Solution

35


IR Building Block


IR3623/IP2003

Overview of Some Power Management Issues - BGUpedesign/slides/Presentation2008.pdfzDC-DC PowerconverterDC Power converter zDC-AC Inverter zAC-AC Cycloconverter Prof. S. Ben-Yaakov,

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