無線充電，或說是無線電力傳輸，隨著行動裝置和生醫研究的
快速崛起和蓬勃發展而受到重視。比起傳統的有線充電，無線充電
有以下兩個優點：操作更安全和充電更方便。然而，無線充電可能
會面臨能量傳輸效率較低的問題，而這正是我們研究亟欲去解決
的。
　　影響能量傳輸效率的因素有很多，其中包括元件的參數變異、
傳輸端與接收端距離的不確定性和能量傳輸介面上的非線性操作等
等。傳統的接收端架構會用固定或可改變的電阻負載，但這樣的做
法仍無法彌補能量效率下降和接收的負載能量不足問題。
　　我們這個研究提出一種含有調整機制去改變輸入介面等效阻抗
和電抗的無線電力傳輸接收端架構。在提出的接收端架構中，有一
個額外的開關加入到整流器的輸出端。搭配不同的開關關閉時間和
不同的後端系統負載，我們可以在接收端輸入介面做到共軛複數阻
抗匹配和提升傳輸效率與接收的負載能量。
　　晶片實作是用0.25-mm的高壓互補式金屬氧化物半導體製程，
量測結果顯示，耦合參數在0.05到0.255的變化範圍下，負載能量可
維持大於2.4瓦，而且最大的負載能量能達到3.33瓦。與傳統的接收
端架構相比，我們提出的架構可提升百分之五十到百分之八十的負
載能量在變動的耦合參數範圍內；模擬更進一步顯示最大的傳輸效
率可達80.37%。

Wireless charging or Wireless Power Transfer (WPT) has become
popular due to the rapid growth in mobile devices and implantable
medical devices. It has the advantages of safer operation and more
convenience compared to the traditional charging method through
electrical cord. However, WPT may suffer from low power conversion
efficiency, which this work is devoted to solving.
There are various sources that can impact the power conversion
efficiency, such as component parameters’ variation, uncertain distance
between transmitter and receiver, and nonlinear operations
of the power transfer interface, etc. The conventional method of
using a fixed load or a resistive load compromises the power conversion
efficiency and further leads to insufficient output power.
The work proposes a WPT receiver architecture with an adjustment
mechanism to vary both the effective resistance and reactance
of the interface. In the proposed receiver, a switch is inserted
at the rectifier’s output. Through different switching timing along
with different loading from the following system, complex conjugate
impedance matching can be achieved at the power transfer
interface, improving the conversion efficiency and output power.
Implementing using a 0.25-mm HV CMOS technology, measurement
results show that an output power of more that 2.4W can
be obtained with coupling factor from 0.05 to 0.255 with a maximum
output power of 3.33W. Depending on the coupling factor, the output power can be improved by 50% to 80% compared with
the conventional structure. Simulations further show a maximum
power conversion efficiency of 80.37%.

Contents i
List of Tables iv
List of Figures v
1 Introduction 1
1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Thesis Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Wireless Power Transfer System 6
2.1 Wireless Power Transfer Block Diagram . . . . . . . . . . . . . . 6
2.1.1 transmitter System . . . . . . . . . . . . . . . . . . . . . . 7
2.1.2 Coupling Coil . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.1.3 Receiver System . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2 Coupling Coil Equation . . . . . . . . . . . . . . . . . . . . . . . 15
2.3 Wireless Power Transfer Specification . . . . . . . . . . . . . . . 18
2.3.1 Wireless Power Consortium, WPC . . . . . . . . . . . . . 19
2.3.2 AirFuel Alliance, AFA . . . . . . . . . . . . . . . . . . . . 19
2.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3 Receiver System with Configurable Effective Impedance 22
3.1 The Operation of Receiver System with Configurable Effective
Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2 Cross-Coupled Rectifier and IsoMOS . . . . . . . . . . . . . . . 28
3.3 IsoMOS Control Circuit . . . . . . . . . . . . . . . . . . . . . . . 29
3.3.1 Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.3.2 Delay Block . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.4 S6-to-S7 Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4 Simulation and Measurement Result 40
4.1 Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.1.1 Matching Network in Transmitter . . . . . . . . . . . . . 41
4.1.2 WPT and Chip Parameters . . . . . . . . . . . . . . . . . 43
4.1.3 Simulation Result . . . . . . . . . . . . . . . . . . . . . . . 46
4.2 Measurement Result . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.2.1 Chip Photo . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.2.2 PCB Board . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.2.3 Testing Method . . . . . . . . . . . . . . . . . . . . . . . . 57
4.2.4 Coupling Coil Measurement . . . . . . . . . . . . . . . . 58
4.2.5 Whole Chip Measurement . . . . . . . . . . . . . . . . . 64
5 Conclusion 72
Bibliography 73

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