デルタシグマ変調を用いた...高虹, 美和俊介, 小堀康功, 邢林小林春夫,...

◎ 高虹, 美和俊介, 小堀康功, 邢林

小林春夫, 高井伸和, 新津葵一（群馬大学）

大森武志, 小田口貴宏, 中西功, 根本謙治

（AKMテクノロジー株式会社）

松田順一（旭化成パワーデバイス株式会社）

デルタシグマ変調を用いたDC-DC変換器制御の検討

1

電気学会電子回路研究会（岡山県立大）

2011年7月1日

2Contents

● Research Background and Objective

● PWM and ΔΣ Controllers in DC-DC Converter

● Feedforward-type ΔΣ Controller in DC-DC Converter

● ΔΣ Controller for Single-Inductor Dual-Output DC-DC Converter

● Conclusion

3Contents





● Conclusion

4Research Background

● Rapid advances of Power DevicesFast switching speed

Application of ΔΣ modulator to DC-DC converter controller becomes feasible.

● Expected advantages- Fast transient response- High efficiency at low load- Spread spectrum of switching noise

5Research Objective

● To show advantages of feed-forward-type ΔΣ controllerover feedback-type in DC-DC converter.

Feedback-type ΔΣ controller one clock signal delay

Feed-forward type no signal delay- small ripplefast response

● To investigate applicability of ΔΣ controllerin single-inductor dual-output DC-DC converter.

6Contents





● Conclusion

7Trade-off of Fast Response and Efficiency

High Switching Frequency

Faster Transient Response Inductor charged and dischargedat high speed

High Efficiency

Reduction of Switch Operation

Low Switching Frequency

Lower Switching Loss

8Problems of PWM Controller

Switching frequency determined by sawtooth wave

Difficult to meet simultaneously both of ・ Fast Transient Response・ High Efficiency

Switching Period

Output of Error Amp

PWM Output

time

time

DC-DC converter with PWM controller

9ΔΣ Modulator Controller

Low input Sparse Pulse Stream(at steady state) (Low switching frequency)

High input Dense Pulse Stream(at transient state) (High switching frequency)

High efficiency:

Fast transient Response:

ΔΣM Controller+

-

Error Amp

Vref

input

Low

highDC/DC Converter Output

⇒

⇒

ΔΣ modulator output

Can meet both

time

10Contents





● Conclusion

11Feedback-type ΔΣ Modulator

Signal Transfer Function Noise Transfer Function

One-clock delay Differentiation=Noise Shaping

12Feedback-type ΔΣ Modulator and Operation

Sampling Frequency∝

Number of Pulses

Ph1 Ph1Ph2 Ph2clocking

Vref -Vref

しきい値

サンプリング周期

Vref

-Vref入力信号

出力信号

積分器出力

0Output Signal

Input Signal

Threshold Voltage

Sampling period

Output of Integrator

Error

Amp

output Switch

on/off

control

131st-order Feedforward ΔΣ Modulator

ぉΣ Low Pass Filter ADCΣ

DAC

＋

―

＋A（in）Ｖout

No Delay Differentiation=Noise Shaping

ぉΣ H(z) Σ

＋

―

＋

E(z)

X（z）Y(z)

STF = 1 NTF=

1st -order FF ΔΣ

142nd-order Feedforward-type ΔΣ Modulator

2nd-order FF ΔΣSTF = 1 NTF=

No Delay 2nd-order Differentiation

15ΔΣ Modulator as DC-DC Converter Controller

Vref+

-Controller

RoutCoutR1

R2

● Feedback ΔΣ modulatorOne-clock signal delay (disadvantage)

● Feedforward ΔΣ modulatorNo signal delay (advantage)

phase & gain margin improvementsmall ripplefast transient response

Vout

LVin

We expect

16Simulation Condition

Vin： 3VL: 4.7uHCout: 47uFRout: 50ΩVref: 600mVFs: 400kHz （PWM）Fs：800kHz(ΔΣ)

Vref+

-Controller

RoutCoutR1

R2

① PWM controller② 1st-order feedback ΔΣ modulator③ 1st-order feedforward ΔΣ modulator④ 2nd-order feedfoward ΔΣ modulator

VoutL

Vin

Boost DC-DC Converter

17Output Ripple Voltage (Simulation Results)

time/mSecs 5uSecs/div

4.605 4.61 4.615 4.62 4.625 4.63

VO

UT

/ V

5.0326

5.0328

5.033

5.0332

5.0334

5.0336

5.0338

5.034

5.0342

5.0344


4.605 4.61 4.615 4.62 4.625 4.63

VO

UT

/ V

4.9906

4.9908

4.991

4.9912

4.9914

4.9916

4.9918

4.992

4.9922

4.9924


4.65 4.7 4.75 4.8 4.85 4.9 4.95 5

VO

UT

/ V

5.0866

5.0868

5.087

5.0872

5.0874

5.0876

5.0878

5.088

5.0882

5.0884

PWM Controller

1st-order Feedback ΔΣ modulator

1st-order Feedforward ΔΣ modulator

2nd-order Feedforward ΔΣ modulator

0.1mV

1.1mV

0.23mV

0.6mV


4.62 4.64 4.66 4.68 4.7 4.72 4.74 4.76 4.78 4.8

VO

UT

/ V

5.004

5.0042

5.0044

5.0046

5.0048

5.005

5.0052

5.0054

5.0056

5.0058

18Transient Response Simulation

Vref

+

-Controller

Cout

50Ω

At 8ms Zout: 10Ω 5ΩAt 10.5ms Zout: 5Ω 10Ω

Zout

19Transient Response Simulation


7 7.5 8 8.5 9 9.5

VO

UT

/ V

4.4

4.6

4.8

5

5.2

5.4


9.8 10 10.2 10.4 10.6 10.8 11 11.2 11.4 11.6 11.8

VO

UT

/ V

4.7

4.9

5.1

5.3

5.5

Zout: 10Ω 5Ω

(Iout: 0.5A 1A）

Zout: 5Ω 10Ω

(Iout : 1A 0.5A）

time/mSecs 2mSecs/div

6 8 10 12 14

IPR

OB

E1 /

A

0.5

0.6

0.7

0.8

0.9

1

PWM

1st- order Feedback ΔΣ modulator

1st-order Feedforward ΔΣ modulator

2nd- order Feedforward ΔΣ modulator

Output Current IoutAt 8ms

At 10.5ms

20Simulation Results Summary

ModulatorState

PWM １st-order Feedback ΔΣ

１st -order Feedforward ΔΣ

2nd-order Feedforward ΔΣ

Steady State

Ripple 0.1mV 1.1mV 0.6mV 0.23mV

TransientState(fall)

Ripple 0.18V 0.15V 0.083V 0.074V

Time 0.68ms 0.55ms 0.28ms 0.28ms

PWM controller case: steady state ripple smallestbut transient response slowest

2nd-order feedforward ΔΣ modulator is the best among 3 ΔΣ modulators.This is due to

- No signal delay- Noise is 2nd-order shaped - High-frequency noise is reduced by LC circuit

①

①

②

① ①

④ ③

②④ ③

③④

21Contents





● Conclusion

22Background of Single-Inductor Dual-Output DC-DC Converter

Conventional Dual-output Converter Signal-Inductor Dual-Output Converter

DC/DC Vout1

Vout2

Vin

DC/DC

DC/DC

Vout1

Vout2

Vin

Inductor L×2Bulky, expensive

Inductor L×1Small, cheap

23Background of Single-Inductor Dual-Output DC-DC Converter

Conventional Dual-output Converter Signal-Inductor Dual-Output Converter

DC/DC Vout1

Vout2

Vin

DC/DC

DC/DC

Vout1

Vout2

Vin

Inductor L×2Bulky, expensive

Inductor L×1Small, cheap

Hot Research Topic

24Operation Principle of SIDO

ｔ

Ｉ L

Inductor Current

Vout1 Vout2

Dual-boost converter

Vin

Vout1

Vout2

L

S1

S3

S2

Dual outputs by time-division usage of inductor

25Simulation Condition

S2

Vin

Vref1

Vout1

+

-ΔΣ変調

ドライバ

Vout2

Vref2+

-ΔΣ変調

L

S1

S3

S1,S2,S3へ

Rout1Cout1

Rout2Cout2 R3

R4

R2

R1

Driver

PWM vs. ΔΣ

PWM vs. ΔΣ

Vin： 3VL: １uHCout1,2: 200uFRout1,2: 200ΩＲ１，３： 9ＫΩＲ2，４：１ＫΩVref1: 500mVVref2: 700mVFs:1MHz(PWM)Fs: ５ＭHz(ΔΣ)

26Simulation Results with PWM Controller

S2

Vin

Vref1

Vout1

+

-ΔΣ変調

ドライバ

Vout2

Vref2+

-ΔΣ変調

L

S1

S3

S1,S2,S3へ

Rout1Cout1

Rout2Cout2 R3

R4

R2

R1

Driver

PWM

PWM

0.32V

0.47V

Vout1 (Vref1=7.0V)

Vout2 (Vref2=5.0V)

27

0.035V

0.018V

S2

Vin

Vref1

Vout1

+

-ΔΣ変調

ドライバ

Vout2

Vref2+

-ΔΣ変調

L

S1

S3

S1,S2,S3へ

Rout1Cout1

Rout2Cout2 R3

R4

R2

R1

Driver

ΔΣ

ΔΣ

Vout1 (Vref1=7.0V)

Vout2 (Vref2=5.0V)

Simulation Results with Feedforward ΔΣ Controller

Smaller ripple voltage

28SIDO & ΔΣ Modulator

● We here showed

ΔΣ modulator is applicable to SIDO converter

● Zout1 changes Vout1, Vout2 change

ΔΣ modulator high switching freq. operation

Vout1, Vout2 recover soon

(fast response and good cross-regulation)

29Contents





● Conclusion

30Conclusion

・ As the DC-DC Converter Controller

ΔΣ Modulator excels PWMMerit: Fast transient response

FeedForward ΔΣ Modulator excels Feedback-typeSecond-Order Modulator excels First-Order

Merits : Small output voltage ripple Fast transient response

・ ΔΣ Modulator applicable to SIDO DC-DC Converter

31Future Work

● Efficiency evaluation of DC-DC converter

with ΔΣ modulator

● Application of ΔΣ modulator to

current-mode control

● Application of ΔΣ modulator to

AC-DC converter

33Simulation Results with Feedforward ΔΣ Controller

Vin：3[V]L:１[uH]Cout1,2:200[uF]Rout1,2:200[Ω]Ｒ１，３：9Ｋ[Ω]Ｒ2，４：１Ｋ[Ω]Vref1:500[mV]Vref2:700[mV]Fs:５[ＭHz]

ＥＡ１

ＥＡ２

ΔΣ１

ΔΣ２

Ｓ１

Ｓ２

Ｓ3

S2

Vin

Vref1

Vout1

+

-ΔΣ変調

ドライバ

Vout2

Vref2+

-ΔΣ変調

L

S1

S3

S1,S2,S3へ

Rout1Cout1

Rout2Cout2 R3

R4

R2

R1

Driver

ΔΣ

ΔΣ

デルタシグマ変調を用いた...高虹, 美和俊介, 小堀康功, 邢林 小林春夫,...

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デルタシグマ変調を用いた...高虹, 美和俊介, 小堀康功, 邢林小林春夫,...