- 學位論文
利用延遲鎖定迴路技術之自動調整切換式電容濾波器設計
Design of Switched-Capacitor Filter With Automatic Tuning Using Delay-Locked-Loop Techniques
摘要
本論文的研究重點分為兩個部份，第一部份：利用電流控制電流差分轉導放大器(Current Controlled Current Differencing Transconductance Amplifier；CCCDTA) 主動元件，並藉由線性轉換(Linear Transformation)的方式合成高階主動混合模式低通濾波器，同時俱有電壓、電流、轉導、轉阻模式。此設計方式具有系統化設計流程、電路設計較簡單、最少主動元件和無電阻以及電容均接地等優點，並且n階濾波器，只需要n個主動元件、n個電容即可達到混合模式濾波器。此晶片採用TSMC 0.18μm 1P6M製程，頻寬為5MHz，電源電壓為±0.9V，功率消耗為2.094mW，晶片面積為0.12mm × 0.23mm (不含PADs)。 第二部份：目標為設計一個自動調整系統（Automatic Tuning System），並使用切換式電容可調濾波器來達成，此濾波器為利用改變責任週期去達到頻寬可調的功能。因積體電路會有製程飄移或溫度的變化，加上許多雜散效應的影響，導致濾波器的頻寬會受到影響；而這個機制就是將濾波器的截止頻率與自動調整系統設定的頻率作比較，修正到預設的結果，將所要的頻寬鎖在固定的範圍，便可以大幅提升濾波器的準確性。然而一般自動調整系統都是使用計數器來做調整，但調整的精密度受限，故本論文是使用充電泵來達成調整的功能，此作法的最大好處是有較高的解析度，可使自動調整系統更為精準。此晶片採用TSMC 0.18μm 1P6M製程，頻寬可以做調整(1.5MHz~5MHz)，電源電壓為±0.9V，功率消耗為6.65mW，晶片面積為0.58mm × 0.43mm (不含PADs)。
並列摘要
The major research of this thesis can be divided into two parts. The first part, a high-order active mixed-mode low pass filter is based on CCCDTA (Current Controlled Current Differencing Transconductance Amplifier ; CCCDTA). It is synthesized by linear transformation. The mixed-mode filter consists of the voltage-mode, transresistance-mode, current-mode, and transconductance-mode, respectively. By using this technique, it has advantages which include systematic design procedures, simple design equations, minimum active elements, without any resistors and using grounded capacitors. If the filter is design by nth-order, it only need n active elements and n capacitors to achieve mixed-mode filter. The high-order active mixed-mode low pass filter is implemented in a TSMC 0.18μm 1P6M CMOS process, the bandwidth of filter is 5MHz and the power consumption is 2.094mW with ±0.9V power supply. The chip area is 0.12mm × 0.23mm without I/O PADs. The second part designs an automatic tuning system using switched-capacitor tunable filter. The cut-off frequency of filter can be tuned by the varied duty cycle. According to process and temperature variation, the cut-off frequency of filter will be influenced. Therefore, the proposed automatic tuning system can improve these problems. By this technique, it can calibrate the cut-off frequency to achieve higher accuracy of filter. The proposed automatic tuning system is suitable to control the bandwidth of switched-capacitor filter, and the process variation and accuracy of filter can be improved by this system. To compare this automatic tuning method with conventional counter or other digital circuits, this method has the advantage of higher resolution. The automatic tuning system is implemented in a TSMC 0.18μm 1P6M CMOS process. The bandwidth of tunable filter is from 1.5MHz to 5MHz. The power consumption is 6.65mW with ±0.9V power supply, and the chip area is 0.58mm × 0.43mm without I/O PADs.