1/33~

2007121

LAB808NCTU

Lab808: Power Electronic Systems & Chips, NCTU, TAIWAN

808DSP

http://pemclab.cn.nctu.edu.tw/Lab-808: Power Electronic Systems & Chips Lab., NCTU, Taiwan

2/33~

Power Electronics Systems & Chips Lab., NCTU, Taiwan

Why Digital Control for Power Electronics?

Power Electronic Systems & Chips Lab.

3/33~

Why Digital Control for Power Electronics?

1. To achieve higher efficiency2. Fast & Flexible: To achieve fast & programmable response dynamic

power management & voltage regulation3. To lower the cost (depends on applications & Manufactures)4. To provide universal, robust, and green power adaptability5. To provide efficient portable power management, Monitoring, and

Control6. To reduce design time time-to-market 7. To realize number of components by using programmable EEPROM

based digital controller 8. To achieve self commissioning digital power supply without external

compensation9. To achieve better & effective system integration 10. To provide system solution for complicated power converting

systems

4/33~

1. To Achieve Higher Efficiency

CRM Buck Inductor @ Standby Operation

iL

0t

)(21

AVGLL ii

B

H

cH

satBB

H

satBB

H

satB

5/33~

Digital Control Squeezes 40 A from Buck Converter

Digital Control Squeezes 40 A from Buck Converter, Benoit Herve, Product Manager, ZilkerLabs, Austin, Texas, Power Electronics Technology, pp. 32-37, August 2007

6/33~

Efficiency as a Function of Control Scheme

Specification: VIN: 3.6V VOUT: 1.8V FOSC = 1.2MHz CIN : 4.7F (Ceramic) L : 3.3H (CDRH3D16 SUMIDA) COUT : 10F (Ceramic) PMOS RDS(ON) : 600m NMOS RDS(ON) : 700m

INC

NMOS

PMOS

LINV

OUTV

OUTCDMode Change

XC9217A18C (VOUT = 1.8V, 1.2 MHz) = 83%

7/33~

Efficiency as a Competition! (NXP1750)

EPRI: Top 15 Average Efficiency (20%, 50%, 100%)

Power

Effic

ienc

y

Source: NXP

NXP improves efficiency by: MOSFET switches replace rectifier

diodes lower losses in output stage Adaptive mode-of-operation adjustment

over the power range

8/33~

Green Mode PWM Control Strategy

SKIP CYCLE

No Load

100% Load

50% LoadINI

PWMV

LI

t

t

t

Maximumon-time

Minimumoff-time

20% Load

9/33~

Typical Operating Modes of a Green Mode Controller IC

Switchingfrequency

fss(40kHz)

Loadpower

Status,pulled up

to VDD

Pout

SSmode

(fixed fsw)

QR mode(valley switching)

fMAX=Oscillator freq.(130kHz)

DCM(max fs)

ICoff

Softstart

Resonantoperation

Fixedfrequency

Frequencyfoldback

load shown is slightly less than over current threshold

t

t

t

Burst operation

Green mode,PFC bias OFF

Constantvolt-sec

fgrmode_mx(40kHz)

This mode applies bursts of 40kHz soft-start pulses to the

power MOSFET gate. The MOSFET gate. The average fsw is

shown in this operating mode.

fsw

Vstatus

Burst operation(hard switching)

POUT,MAX

fQR_MIN (internally limited to 40kHz)

10/33~

Output Characteristic and Auto-Restart

Typical Output Characteristic for LinkSwitch Based 5.5 V, 0.5 A Charger with Specification Limits. (PI)output current (mA)

outp

ut v

olta

ge (V

)

10

9

8

7

6

5

4

3

2

1

00 100 200 300 400 500 600 700

115 VAC230 VAClimitsauto-restart

11/33~

To Achieve Higher EfficiencyVariable-Frequency Variable-Duty ControlLower Switching Higher EfficiencyRandom PWM Lower EMI

Rs1

Kv

AD

AD

Vs

1Kv

1dcV

2dcV

1C

2C

Li

Q2

Q1

AD

1Ko

Vdc2

AD

1Ko

Vdc1

PWM2

PWM1

PWM2

1oi

2oi

PWM1

DIGITAL PFC CONTROLLERKrK'vd Dc(z) Kpc

Kpv

multiplier

ZOH

-+

Vx Vc_+

Vref

sinusoidal reference

current loopcompensator

voltage loopcompensator

+-

PWM Modulator

KY=AB B

A Dc(z)

12/33~

2. Fast & Flexible

High

HighResponse speedLowLow

Flex

ibilit

y

Microcontroller AnalogPWM

Digital PWM Controller

AnalogPWM

DSPController

Microcontroller

Si8250 Digital Power Controller

13/33~

To Achieve Fast & Programmable Response

Intel Pentium IV

Pentium IV55,000,000 Tz0.13 m 3.2GHz1.7VRated Power: 92WPeak Power: 110W

VRM

14/33~

To Achieve Fast & Programmable Response

ADC Controllaw DPWM

Vin

IL IO VO

RESR

CO

Digital Controller L1

L2

L3

L4

15/33~

To Achieve Fast & Programmable Response

Vq

VoVref

(Vo)max

e4321

01234

Vref

VsenseSENSE A/D converter

e[n]Table A

Table B

Table C

Ts

TsTs

e[n1]

e[n2]

d[n]

d[n1]

Table-Lookup Digital Controller Digital PWM Generator

To Achieve One-Cycle Dead-Beat Response

16/33~

To Achieve Fast & Programmable Response

Intel: VRM (Voltage Regulator Module) and Enterprise Voltage Regulator-Down (EVRD) 11.0 Design Guidelines, Nov. 2006.

Adaptive voltagepositioning offsetVOFFSET (40mV)

Nominal setpoint voltage

VSET (2.0V)

Dynamic voltagetolerance, VDYN-(100mV for 2s)

Initial voltage drop is mainly due to the product

of the load current step and ESR of the capacitors.

V = I ESR.(ESL effects are ignored)

Output voltageVOUT (50mV/Div)

Steady state voltage athigh current is approximatelyVSET VOFFSET IOUT RSENSE

Output current transientstep, I = 0 to 14A(5A/Div)

m5.2 GX;-MV Sanyo F15006 ;H5.2 SENSEOUT RCL

17/33~

3. To Lower the Cost (Simple Hardware)

Load

ACInput

Ls

Battery

Lo

Q2

Q1 Q3

Q4

Q5 Q6

D1

D2

D3

D4

D5

D6

D7

D8

T1

C3

Co

CT3CT2K2

CT1

C1

C2

F2

F1 K1 J1

Ro

18/33~

3. To Lower the Cost (Simple Hardware)

Higher integration Smaller size

Enables complex, non-linear control algorithms Higher efficiency Faster control response Tighter regulation

Firmware-programmable Faster time-to-market Easily customized

Lower cost Fewer components Easier to test More reliable

Source: Silicon Laboratory

19/33~

Digital Solution for Performance/Cost Improvement

Provides more functions than analog

Smart powerDigital Power Solution!

Programmable via PMBus protocolProgrammable (sequencing, Vo)Monitoring (fault)

Performance superior tha analog Efficiency optimization for multi-mode operation

Higher efficiency & faster response Power OS: self-tuning/diagnosis Performance/functions beyond analog power

Take advantage of VLSI process VLSI

performance superior than analog

13K Gates0.25um CMOS

0.22 mm2

GUI powersupply

USB PMBusPC

VINVOUT

GUI powersupply

PMBus VINVOUT

OR

Digital Filter Equivalent

Vout

R3

R1

R2

C1

C2 C3

VcompReference

No external components

20/33~

Control Techniques Cuts Flyback Input Capacitance

Rahul Joshi, "Control Technique Cuts Flyback Input Capacitance," Power Electronics Technology, April 2007.

No PFC for low power applications Hold-up time requirement for critical applications Reduction of input capacitance for desired hold-up time DCM with Fixed-Frequency or Duty-Cycle Extension

21/33~

4. To Provide Universal and Green Power Adaptability

Universal input Reliable Efficient Standby Power System solutions

22/33~

5. To Provide Efficient Portable Power Management

AD FSM

phonebookRTOS

ARQ

Keypad,Display

Control

Coders

FFT Filters

Accelerators(bit level)

analog digitalDSPcores

C core(ARM)

Logic

Dedicated Logic

Analog Basebandand RF Circuits

CommunicationAlgorithms Protocols

Power Management

DC/DC Battery Charger Power Drive

23/33~

6. To Meet the Voltage Scaling Requirement

5 factors of dynamic power dissipation and low power design strategies

Supply voltage (voltage scaling)Switching activity (scheduling)Total no. of transistors (circuit minimization)Operating frequency (IC layout, process innovation)Physical capacitance (process innovation)

These parameters are not completely orthogonal and cannot be optimized independently.

NfCV21P c

2ddD

VDD

C

a a

24/33~

7. To Speedup Design Process

Analog Controller

GateDrive

VOUT

12VDigital controller

GateDrive

VOUT

12V

VREF

-50

0

50phase response

10 0 101

102

10 3 10 4 10 5

frequency(rad/sec)

10 0 101

102

103

10 4 10 510

1

102

103

magnitude response

frequency(rad/sec)

(a)

(b)

Digitalcompensator

DigitalmodulatorVREF

25/33~

7. To Speedup Design Process

Gain

Freq.FZ1 FP0 FZ2 FP1 FP2

Bode plot Analog Controller

GateDrive

VOUT

12VDigital controller

GateDrive

VOUT

12V

VREF

(a)

(b)

Digitalcompensator

DigitalmodulatorVREF

26/33~

Comprehensive, Low-Cost Development Kit

Source: Silicon Laboratory

Complete development kit to simplify design: Real-time firmware kernel

Greatly reduces firmware design Automated development tools

Compensation Designer/Simulator Timing Designer/Simulator System and MCU Configuration Wizards

Si8250-based half-bridge DC/DC target board All necessary cables and a country specific power

supply Full Development Kit for only $199

27/33~

8. To Realize Complex Control Algorithm

Rectifier Charger Inverter

T2

T1110/220V50/60 Hz

+

_

ACload

EMI 3-phase

load

C1

C2

Motor/Generator Flywheel

Battery

uud

Power Factor Control

Regenerative Braking Control

DC-Link Voltage Regulation

DC-Link Cap. Minimization

PWM Control Vector Control Current Control Voltage Control Power Flow Control Auto-Tuning

28/33~

8. To Realize Complex Control Algorithm

Current, Voltage& Temp Sensor

Gate Driver &Fault SensingGate Driver &Fault Sensing

Gate Driver &Fault SensingGate Driver &Fault Sensing

Gate Driver &Fault SensingGate Driver &Fault Sensing

Gate Driver &Fault SensingGate Driver &Fault Sensing

ADCADCIs

olat

edPo

wer

Supp

lies

Isol

ated

Pow

erSu

pplie

s

DSPFPGATaxi

TransmitterTaxi

Transmitter

Taxi

Rece

iver

Taxi

Rece

iver

Rectifier Charger Inverter

T2

T1110/220V50/60 Hz

+

_

ACload

EMI 3-phase

load

C1

C2

Motor/Generator Flywheel

Battery

29/33~

Rectifier Charger Inverter

T2

T1110/220V50/60 Hz

+

_

ACload

EMI 3-phase

load

C1

C2

Motor/Generator Flywheel

Battery

8. To Realize Complex Control Algorithm

30/33~

9. To Achieve Self-Compensation Digital Power Supply

31/33~

10. To Achieve Better & Effective System Integration

AdaptiveFuzzy Logic

VoltageRegulator

Referencesignal

CurrentRegulator

PredictedCurrent Control

PWM Gate Drive

Multiplier

Vdc reference

Ipv

VpvVdc bus

Currentsensor

PowerTransformer

Grid

LL

Boost Converter Inverter Grid connected

Diode

SB S1

S2 S4

S3

+

RS-232USB

SNMPTCP/IP

Monitoring Software

32/33~

Analog Control is Inflexible and BulkyExternal passive components: Fixed control response and timing Change with age & temperature Consume space/increase cost

External protection circuits: Fixed protection settings Consume space/increase cost

Other external circuits: Supplement controller function Fixed functions Consume space/increase cost

RFI filter and surge

suppression

InputRectifiersAnd filters

Tempsensor

IPKsensorIPK

Temp

Power Stages OutputfiltersVoutVin

IC biassupply

Crowbarcircuitry

Error amp

VREF

ILIMcomparator

UnderVoltagelockout

Controllogic

modulator

ControlInterfacecircuits

LoopCompensationcomponents

Soft-startcomponents

ThresholdSetting

components

ThresholdSetting

components

Inputovervoltageprotectioncircuitry

Over tempprotectioncircuitry

Specializedtiming

circuitry

Outputovervoltageprotectioncircuitry

Vout

IPK

tem

p

OVP

OVP(to controller logic)

Gat

e tim

ing

sign

als

Leading-edgeBlank timingcomponents

VINFeedforwardcomponents

ModulatorTiming

components

Other feed-forwardsignals

Controller

33/33~

Digital Control is Adaptive and CompactEntire control function: Power control + power management Minimizes space, reduces BOM

- Significant component reduction- Built-in temperature sensor

Dynamic control response: Nonlinear control response- Faster transient response Dead time control- Higher Efficiency

Programmable operation: Fault protection and recovery Adaptive control response Timing optimization Feed forward algorithms Programmable soft-start ramp System power mgmt tasks

RFI filter and surge

suppression

InputRectifiersAnd filters

Tempsensor

IPKsensorIPK

Temp

Power Stages OutputfiltersVoutVin

IC biassupply

Si8250Crowbarcircuitry

Other feed-forwardsignals

System management processor

OSC &CUP

supportCUP

memoryDigital

peripheralI/O

12 bitADC

Vout

Control processor

100MHzADC &VREF

IPKLimiter &

OCPIPK

FilterDSP

engineDPWM

Gat

e tim

ing

sign

als