具分段多項式變容二極體補償技術之溫度補償晶體振盪器

A Temperature-Compensated Crystal Oscillator with Piecewise Polynomial Varactor Compensation

黃昱瑋(YU-WEI HUANG)

指導教授 ： 林宗賢

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202101080

摘要

在通信及物連網應用中都需要精準及低功耗的時脈產生器電路。本論文針對這些應用提出了低功耗32.768千赫茲 RC振盪器以及具分段多項式變容二極體補償的溫度補償晶體振盪器。

第一個作品提出了低功耗32.768千赫茲 RC振盪器。此振盪器透過比較器偏移電壓補償技術來達到好的頻率精準度。振盪器在1.8-V電壓源下總消耗電流為355 nA。本作品以TSMC 180-nm製程實現，核心面積為0.192 mm2，在 -40°C到80°C的溫度範圍內，頻率精準度為±0.214%。

在第二個作品中，我們提出了一個採用分段多項式變容二極體補償的溫度補償晶體振盪器，此設計可以用來解決晶體振盪器原先大約數10ppm的頻率誤差。此外，透過振幅控制迴路讓晶體振盪器在溫度、電壓和製程變化下都能有穩定的表現。本作品採用TSMC 180-nm CMOS製程製造，操作頻率為40百萬赫茲，核心面積為0.282mm2，在1.8-V電壓源下總消耗電流為0.3 mA。量測的頻率精準度為±5.75 ppm。

關鍵字

晶體振盪器 ； 溫度補償晶體振盪器 ； 振幅控制迴路

並列摘要

In communication and IoT systems, low power and accurate frequency generator is required. In this thesis, a low power 32.768-kHz RC oscillator and a temperature-compensated crystal oscillator (TCXO) with piecewise polynomial varactor compensation are proposed for those applications.

In the first work, we propose a low-power 32.768-kHz RC oscillator. A comparator offset compensation topology is adopted to improve the frequency accuracy over temperature. The whole oscillator consumes only 355 nA from a 1.8-V supply. This RC oscillator is fabricated in the TSMC 180-nm CMOS process with a core area of 0.192 mm2. The measured frequency accuracy is ±0.214% over temperature range from -40°C to 80°C.

In the second work, we propose a TCXO with piecewise polynomial varactor compensation, which can compensate the crystal intrinsic frequency inaccuracy, which is in the order of tens ppm. In addition, an amplitude-control loop (ACL) is incorporated to maintain a stable XO operation under process, temperature, and supply voltage variations. This clock generator is fabricated in the TSMC 180-nm CMOS process with a core area of 0.282 mm2. The operation frequency is 40MHz and its current consumption is 0.3 mA from a 1.8-V supply. The measured frequency accuracy is ±5.75 ppm over temperature range from -40°C to 90°C.

並列關鍵字

Crystal Oscillator ； Temperature-Compensated Crystal Oscillator ； Amplitude Control Loop

參考文獻

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