臺灣博碩士論文加值系統

本論文提出一個低互擾式單電感雙輸出降壓型電壓調節器。經由調整相序之方式，使此切換式電壓調節器可以擁有架構簡單、固定的切換頻率以及低互擾之特性。與單電感單輸出電壓調節器相比，單電感雙輸出電壓調節器具有降低面積、節省元件與成本等優點，但單電感雙輸出電壓調節器中，由於兩組輸出共用一組電感所提供之能量，因此當其中一相發生暫態，另一相之電壓會受到影響，稱為互擾，常見解決互擾之方式為不連續電流導通模式控制，但此控制法有輸出功率限制以及輸出漣波過大等缺點。
在本論文中提出了換相式單電感雙輸出之電路模型，使其在連續電流導通模式控制下具有低互擾之特性，且無輸出功率之限制，實驗結果顯示輸出功率可提供約1瓦特。並依此架構由電壓模式控制進行模型推導，設計一專為換相式單電感雙輸出設計之控制晶片，此晶片是由台灣積體電路公司0.35微米製程所實現。模擬結果顯示經由換相之控制，任一相之負載變動對於另一相造成之互擾可降低為普通電壓模式控制之五分之一以下。

A Phase Sequence Interchange (PSI) scheme which can provide low cross regulation for SIDO buck regulator is proposed. By applying the PSI scheme with the voltage-mode control, the SIDO buck regulator has simple circuit design, fixed frequency and low cross regulation characteristics. Compared to the same purpose of using two single-inductor single-output (SISO) voltage regulators, the SIDO voltage regulator has advantages of area efficiency, less usage of passive component and lower cost. However, because the two outputs of the SIDO regulator share the same incoming energy from the single inductor, when one phase is doing transient, the other phase will suffer from the voltage disturbance, which is called cross regulation. A common method to solve the cross regulation problem is adopting discontinuous conduction mode control, nevertheless, this control method easily leads to large output voltage ripple with limited power output. Therefore, the proposed PSI scheme SIDO buck regulator is intended to work in continuous conduction mode to enlarge the output power supply capability. The circuit model derivation and IC chip design for the PSI scheme are illustrated in detail. The IC chip is fabricated by TSMC 0.35µm process. Simulation results show that during one phase transient, the cross regulation occurs in another phase is reduced to less than one-fifth of the cross-regulation effect from the normal voltage-mode operation of the SIDO buck regulator.

摘要 I
Abstract II
Acknowledgements IV
Contents V
List of Tables VIII
List of Figures IX
Chapter 1 Introduction 1
1.1 Background 1
1.2 Motivation 3
1.3 Thesis Organization 5
Chapter 2 Introduction of SIMO Regulator 7
2.1 Structure 7
2.2 Operation Principle 8
2.3 Efficiency 11
2.4 Load Regulation and Line Regulation 12
2.5 Load Transient Response 13
2.6 Cross Regulation 14
Chapter 3 Control Methods and Recent Researches 17
3.1 Control Methods 17
3.1.1 Time Multiplexing with DCM Operation [4][5] 17
3.1.2 Time-multiplexing method with freewheel state [2][3][5] 22
3.1.2 Comparator Control with one loop compensation [2][3] 25
3.1.4 Time multiplexing with CCM fixed frequency operation 28
3.2 Design Consideration and Recent Researches Comparison 30
Chapter 4 Phase Sequence Interchange Scheme for Low Cross Regulation 35
4.1 Phase Sequence Interchange Scheme 35
4.2 Model of the PSI Scheme 38
4.2.1 Model of Voltage-mode ontrolled SIDO buck regulator 39
4.2.2 Compensator Analysis 49
4.3 Stability Analysis 51
4.3.1 Uncompensated SIDO Buck Regulator 51
Chapter 5 Circuit Implementation 61
5.1 System Structure 61
5.2 Circuit Design 63
5.2.1 Bias Circuit [10] 63
5.2.2 Error Amplifier 63
5.2.3 Comparator [10] 65
5.2.4 RAMP Oscillator 66
5.2.5 Phase Sequence Determination Circuit 68
5.2.5 Bandgap Voltage Reference [12] 69
5.2.6 Soft-Start Circuit 71
5.2.7 Feedback Signal Select Circuit 72
5.2.8 Dead-Time Control Circuit 73
5.2.9 Power MOSFET [13] 73
Chapter 6 Simulation and Experimental Results 77
6.1 Layout Consideration 77
6.2 Low Cross Regulation SIDO Buck Regulator 78
Chapter 7 Conclusions and Future Works 89
7.1 Conclusions 89
7.2 Future Works 89
Bibliography 91

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