single inductor dc-dc converter with bipolar outputs using ......input voltage vin：3.5v inductor...

GunmaUniversity Takai

LaboratoryAnalogCircuit

Single　Inductor　DC-DC　Converterwith　Bipolar　Outputs　using　Charge　Pump

Kenji Takahashi,Hajime Yokoo,Shunsuke Miwa,Kengo Thusida,Hiroyuki Iwase,Kazuki Murakami,Nobukazu Takai,HaruoKobayashi,Takahiro Odaguchi,Shigeki Takayama,Isao Fukai,and Jun-ichi Matsuda

Graduate School of Electrical EngineeringFaculty of Engineering

Gunma University,Gunma Japan Asahi Kasei Toko Power Devices Corporation

2010年12月13日月曜日

GUNMA UNIVERSITY TAKAI-LAB

Outline

2

①Introduction

②SIMO DC-DC Converter

③Simulation Results

④Conclusion



Outline

3

①Introduction



④Conclusion



Introduction

4

High Efficiency and Extremely Small System Solution

Industry Demands

Switching Regulator

Linear Regulator Circuit Size：SmallEfficiency 30～60％

Switching Regulator Efficiency 70～90％ Circuit Size：Large

Conventional Power Supply Circuits

Optimize Efficiency


GUNMA UNIVERSITY TAKAI-LAB 5

Digital Camera

Positive Voltage：１５V

Negative Voltage：−８V

OLED Display

Positive Voltage：５VNegative Voltage：−２V

Vop

Vom

Multi Output Power Supply Circuit

Switching Regulator

Introduction





One Inductor is Removed

Vop

Vom

Vop

Vom

Single Inductor


High Efficiency and Extremely Small System Solution

Industry Demands

Introduction

SIMO DC-DC ConverterSIMO:single inductor multi output



Outline

7

①Introduction



④Conclusion


Vom = −Vop + VF


Conventional Circuit

8

ON

OFF

OFF

Negative Voltage：

Negative Output Depends on Positive Output

!!

S1

S2

S3

Sf

CL D

Vop

VomVi

Positive

Negative

S1

S3

Stage2

S2

s

ON ON

ON ON

Stage1

OFF

OFF

Sf

OFF OFF

OFF OFFOFF ON ON

OFF

OFF OFFON ON

TsIL

Inductor Current WaveformTs：１cycle

Cause：S2 & S3 are on Simultaneously　

Stage3

Timing DiagramSIMO DC-DC Converter



テキスト

S1

S3

Stage2

S2

s

ON ON

ON ON

Stage1

OFF

OFF

Sf

OFF OFF

OFF OFFOFF ON ON

OFF

OFF OFFON ON

TsIL

Stage3

Conventional Timing Diagram

sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON

Ts

Ip

IB

IL

Change!

Proposed Timing Diagram

Tp Tm

Ts：１cycleTs：１cycle

Inductor Current WaveformInductor Current Waveform

Inductor Current is Changed

The duty ratio of each switch is fixed

Change of Timing Diagram



sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON

Proposed　timing　diagram

Ts

Ts：１cycle

T１ T２ T３ T４ T５ T６Ip

IB

ILInductor Current Waveform

Ip2

!!

S1

S2

S3

Sf

CL D

Vop

VomVi

SIMO DC-DC Converter

Operation of Switch Sf

Maintains the value of the current in the inductor.



sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON


Ts

Ts：１cycle


IB


Ip2

Stage1

!!

S1

S2

S3

Sf

CL D

Vop

Vom

IL =Vi

Lt =

Ip − IB

T1t


S1: Turns on　☞

Vi

Ip2


Inductor L stores energy from voltage Vin

Current that flows to inductor L



sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON


Ts

Ts：１cycle


IB


Ip2

IL =Vop − Vi

Lt =

Ip − IB

T2t

Stage2

!!

S1

S2

S3

Sf

CL D

Vop

Vom


S２：Turn on・・・Inductor L supplies its energy to output terminal of Vop

＋

ー

Vi

Ip2

IL =Vi

Lt =

Ip − IB

T1t

Equation of Stage1 Vop =T1 + T2

T2Vi




sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON


Ts

Ts：１cycle


IB


Ip2

Stage3

!!

S1

S2

S3

Sf

CL D

Vop

Vom


Sf：Turn on・・・

Vi

Ip2


The current of the inductor is maintained with the free wheel switch



sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON


Ts

Ts：１cycle


IB


Ip2

Stage4

!!

S1

S2

S3

Sf

CL D

Vop

Vom

IL =Vi

Lt =

Ip2 − IB

T4t


S１:Turn on・・・

Vi

Ip2

14


Inductor L stores energy from voltage Vin




sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON


Ts

Ts：１cycle


IB


Ip2

Stage5

!!

S1

S2

S3

Sf

CL D

Vop

Vom


S３：Turn on・・・

　　　　

Vi

Ip2＋ー

15

IL = −Vi − Vc

Lt = −Ip2 − IB

T5t


Charge pump capacitor Cc charges energy from the inductor




sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON


Ts

Ts：１cycle


IB


Ip2

Stage6

!!

S1

S2

S3

Sf

CL D

Vop

Vom


Vi

Ip2＋ー

16


Sf：Turn on・・・The current of the inductor is maintained with the free wheel switch



sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON


Ts

Ts：１cycle


IB


Ip2

Stage1

!!

S1

S2

S3

Sf

CL D

Vop

Vom

IL = −Vi − Vc

Lt = −Ip2 − IB

T5t

Vom = −T4 + T5T5

Vi


　　　　　

S１：Turn on・・・Energy of capacitor is discharged and negative voltage Vom are given

ー

＋

Vi

Ip2＋ー

Equation of Stage4

Equation of Stage5

IL =Vi

Lt =

Ip2 − IB

T4t




sStage1 Stage2

Stage3Stage4

Stage5

S1

S3

S2

Sf

ON

OFF ON

OFF

ON

OFFOFFON

ONOFF OFF

OFF

OFF

Stage6

ON

Propose　timing　diagram

Ts

Ts：１cycle


IB

ILinductor current waveform

!!

S1

S2

S3

Sf

CL D

Vop

Vom

Vom = −T4 + T5T5

Vi + VF = −D4 + D5D5

Vi + VF

Vop =T1 + T2

T2Vi =

D1 + D2D2

Vi


Negative output voltage can be changed independently

Ip2

Vi





Outline

19

①Introduction



④Conclusion



Simulation Results

20

Simulation Condition

Switching Frequency：500kHz

Input Voltage Vin：3.5V

Inductor L：2u

Output Capacitor Cout：10u

Load Resistance Ro：15ΩCharge Pump Capacitor Cc：5u

Vi

!!

S1

S2

S3

Sf

CL D

Vop

Vom




Positive Output Voltage:7V

Simulation Results(Conventional)

Positive Output Voltage:10.5V Positive Voltage

Negative Voltage

Positive Voltage

Negative Voltage

Negative Output Voltage:-5.93V Negative Output Voltage:-9V



Simulation Results(Conventional)

Negative Voltage：Vom = −Vop + VF

A negative voltage depends on a positive voltageConventional Circuit

Positive Voltage Positive Voltage　　Ripple (Vpp) Negative Voltage Negative Voltage

　　Ripple (Vpp)

6.89V10.1V

75.5mV119.7mV

-5.9V-9.1V

54.3mV87.9mV


Positive Output Voltage:6.7V


Simulation Results(Proposed)Positive Output Voltage:6.7V

Positive Voltage

Negative Voltage Negative Voltage

Positive Voltage

Negative Output Voltage:-4.54V Negative Output Voltage:-6.3V



Setting output voltage Positive Voltage Positive Voltage　　Ripple (Vpp) Negative Voltage Negative Voltage

　　Ripple (Vpp)

6.7V 50.8mV-4.5V-6.3V

20.8mV27.1mV

50.8mV6.7V

Proposed Timing Daigram

Positive Voltage Positive Voltage　　Ripple (Vpp) Negative Voltage Negative Voltage

　　Ripple (Vpp)

6.9V10.1V

75.5mV119.7mV

-5.9V-9.1V

54.2mV87.9mV

Conventional Timing Daigram

Voltage Ripple has Decreased

Simulation Results



Inductor Current Waveform

Conventional

Proposed

Current Ripple (Vpp)

630.4mA1.35Ａ

Inductor Current Waveform

Inductor Current Ripple is Reduced by 50%

Conventional

Proposed

At The One Cycle

Proposed

Inductor L is two charge ＆discharge

Inductor L is one charge ＆discharge

Conventioanl



Output Voltage Waveformtime(ms)

（V）

（V）

7.0

Negative output voltage depends on positive output voltage

Transient Response (Conventional)

Transient Response



time(ms)

Negative output voltage independent of positive output voltage

Cross-regulation is Improved

Output Voltage Waveform

Transient response(Proposed)Transient Response



Outline

28

①Introduction



④Conclusion



Conclusion

29

A new timing diagram is proposed

・Independent positive and negative output voltage

・Voltage ripple and inductor ripple less than conventional timing diagram

・Cross-regulation is improved


single inductor dc-dc converter with bipolar outputs using ......input voltage vin：3.5v inductor...

Documents