multi-phase full/half wave type resonant …...vr t0 t1 ta t2t3 ts vi 0 io 0 io 0 vr ir pwm ids v...

Multi-Phase Full/Half Wave Type　Resonant Converter

with Automatic Current Balance against Element Variation

Chen-Hao Zhang*, Yi-Fei Sun, Tran Minh Tri,Yasunori Kobori, Anna Kuwana，Haruo Kobayashi

Gunma University

1Contents

•Research background•Full/Half wave type soft switching converter •Multi-phase soft switching converter• Automatic current balance technology• Conclusion

2Contents


3Research Background

・CPU for server

DC 12V

SocketAC-DC converter

AC 100V DC-DC converter

DC 1.3V, I >100A

・LED Display ・Digital Camera ・Smartphone

Large CurrentFast Response

Supplies

4

Soft-SwitchingZVS, ZCS

Multi Function

Down-SizingLow Cost

Large Current

FastResponse

HighEfficiency

Low Noise

SIMO

EMI Reduction

IC, SIMO

Ripple Control(Hysteretic Cont.)

PWM ControlBuck Converter

Multi-Phase+ Soft-

Switching+Automatic Current Balance

EMI Reduction+ Ripple Control

Multi-Phase

Power supply research of Gunma University

Today’sReport

C6-4

5Today’s Presentation

Large Current Multi-Phase

PWM ControlledBuck Converter

Fast Response

High Efficiency

Ripple Controlled

Multi-PhaseSoft Switching

ConverterC6-1：Reported

Full/Half Wave Resonance

Already produced4 ~ 6 Phase

Problem 1

ElementVariation

Problem 2

CurrentImbalance

6Research Objective

　　Development of power supply with ・ Multi-phase soft switching converters　　　　　 with full or half wave resonance ・ Automatic current balance technology against resonant element variation

1) How to configurate the multi phase constructions when there is no fixed clock pulse? 2) How to control the current balance automatically?

Technical Problems

Objective

7Contents


8Soft　Switching Converter (Full Wave)　

Soft　Switching Converter with Full Wave Resonance

Fig. Full wave soft swiｔching converter

＊Resonant elements Lr, Cr, Dr are added.＊SW turns ON at Vr=Vd.＊Vo=D･Vi　　：D is the duty ratio of PWM.

Fig. Signals of ｆull wave converter

＊Conditions: F=760kHz Vi=12V, Vo=7.0V, Io=1.0A Lo=50µH, Co=470µF Lr= 20µH, Cr=100pF

Ir

Ids

Vr T0 T1 T2 T3Ta Ts

Vi0

Io

0

Io0

Vr

Ir

PWM

Ids

Turn onVLO

Comp2

9Soft　Switching Converter (Half Wave)　

＊PWM Duty shows period of TOFF.＊Duty ratio is represented by inductor current.＊Operation frequency depends on output current Io.

Fig. Half wave soft swiｔching converter

＊Resonant Dr is deleted.＊SW turns ON at Vr=Vd but Vo is not =D･Vi 　(D is duty ratio of PWM)

Fig. Signals of half wave converter

Comp2

10Contents


11Multi Phase Buck Converter

★Twoｰphase is provided by Flip-Flop which divides the clock pulse.

＊PWM2 is opposite phase. ＊Ripple of ΣIL is half of IL1 .

PWM1

IL1

PWM2

IL2

ΣIL

SW

CoVi

Di

AMPVo

Vr

R L

Main-converter

SAW1

Div.

Sub-converter

PWM1

Comp

L1

Vi

Clock

CK-controller

Ph1

Ph2

ΣIL

PWM2

SAW2

IL1

IL2

CK1

SAW1

ΔVE

12Dual-Phase Soft-switching Converter

●Opposite phase is generated like ripple-controlled converter.

Fig. Dual phase switching converter Fig. Signals of dual phase converter

Io

SAW1

Vpeak/2Compare SAW2

180°delay

13Contents

•Research background•Full/Half wave type soft switching converter •Automatic current balance technologyConclusion

14Imbalance of Dual-Phase Converter

LC L(C+ΔC)Temperature or other effects Vo↓ Io↑ Imbalance

PWM1

Resonance

SAW1

ΔT

element variation

Switch on time is stable, but the closing time is extended

off

on

TTTVV

oninO ＝

15

＊When phase2 is shift to delay, the current IL2 will decrease. ＊Detecting the current balance, When IL2 > IL1, make the bias voltage VB down. ⇒ Phase 2 shifts delayed and IL2 is decreased.

Automatic Current balance Technology

PWM1

IL1

PWM2

IL2

ΣIL

VB

Ph2

Vc

16

＊Current balance 1) Current balance with ideal elements 2) Current imbalance with element variation

●Demerit of current imbalance 1) Output ripple increases! 2) Inductor current increases & loss goes up & heat up. 3) Semiconductor (SW) needs　　large current & heat capacity

Imbalance of Dual-Phase Converter

Fig. Current balance with ideal elements

Fig. Current imbalance with element variation

Io

IL1

IL1≠IL2≠Io/2

IoIL1/IL2

IL1＝IL2＝Io/2

IL2Imbalance

17Automatic Current balance Technology

Current balance control signal

PWM2

NEW PWM2

Vpeak-hold

SAWVc

Vc-α

VC

SAWCompare PWM2

VC+α

SAWCompare New PWM2

Balance

18Generation of Four-Phase Pulses

Voltage Divider & Comparator

Operation waveformMain PWM

SAW

SAW Generator & Peak Hold

PWM4

PWM3

PWM2

PUL4

PUL3

PUL2

time/mSecs 2uSecs/div

2.206 2.208 2.21 2.212 2.214 2.216 2.218

V

2

4

6

8

10

12

VPeak-hold

[V/V]

Reset

PWM1

PWM2

PWM3

PWM4

SAW

Vcomp PUL2 PUL3 PUL4

[V/V]

[t/ms]

Fig. Signals of Four-phase converter

19Current Balance of four-phase Converter

Large load current achieved

Good current balance during transient response

Good current balance

IL1, IL2, IL3, IL4

[I/A]

[t/mS]

Io

IL1, IL2, IL3, IL4

[t/mS]

[I/A]

Without element variations ⊿L, ⊿TCOT(=⊿C), ⊿VS/H

★Simulation Result

20Imbalance current (Dual-phase)

10μH 11μH

InductorMain power supply

+ 10%

Io = 6AIL1 =4.3A , IL2 =1.7A

ΔIL = (IL1 -IL2 ) -- = |4.3-1.7|=2.6A Error Ratio: δ = (Io/2-In)/Io/2 =(3-1.7)/3=> 43%

●Two Phase: With element variation (Inductance)

☹

Fig.Dual-phase current imbalance

21Balance current(Dual-phase)

Io = 6AIL1 =IL2 =3A


●Two Phase ：Result of proposed method with good current balance

� Fig. Multi-phase current balance

10μH 11μH


+ 10%

22Imbalance current (Multi-phase)

10μH 11μH


+ 10%

Io = 8.58AIL1 =5.43A , IL2 =3.15A

ΔIL = (IL1 -IL2 ) -- = |5.43-3.15|=2.28A Error Ratio: δ = (Io/2-In)/Io/2 =(4.29-3.15)/4.29=> 27 %

●Four Phase: With element variation (Inductance)

☹Fig. Multi-phase current imbalance

23Balance current(Multi-phase)

Io = 6.81AIL1 =IL2 =3.40A


●Four Phase ：Result of proposed method with good current balance

�

Fig. Multi-phase current balance

10μH 11μH


+ 10%

24Conclusion

l The peak hold voltage is extracted by the peak hold circuit to compare it with the SAW1 signal, producing a SAW2 signal with a 180°delay, thereby implementing a dual wave converter without a clock signal. This method has automatic adjustment capability and has faster response speed than traditional PLL methods.

l We have proposed multi-phase full wave and half wave type voltage resonant converters with automatic current balance against the LC elements variation.

25

Thank you for your attention

26

Q&Aに必要と思われる資料を以下に添付しておくと良い

27Operation of Buck Converter

Vin Vo

Q L

CDPWM

Buck　Converter

Vo+-

L

C+

-

+-

Vo+

-

Vin +-

L+ -

C

Q VEO

VEO

DVin

On State: Q on D offIL

IL

VQ

IL

VEO

Ton Toff

ΔIL+

ΔIL-

Off State: Q off D on

Volt-second balance

VLon = Vin－Vo= Ｌ･（⊿ｉL+/⊿ton）

VLoff =－Vo= Ｌ･（⊿ｉL-/⊿toff）

⊿ｉL+ = ⊿ｉL-

On State

Off State

Vo = Vin

TsVQ

multi-phase full/half wave type resonant …...vr t0 t1 ta t2t3 ts vi 0 io 0 io 0 vr ir pwm ids v...

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