應用於超寬頻無線通訊系統之低功率可變增益放大器

Low Power Variable Gain Amplifier for UWB systems

胡運忠(Yun-Chung Hu)

指導教授 ： 陳淳杰

中原大學/工學院/電子工程研究所/碩士(2007年)

https://doi.org/10.6840/cycu200700864

摘要

由於近年來無線網路技術的蓬勃發展，使得相關的系統電路不斷推出且運用在我們的日常生活中，如GSM和CDMA，藍芽﹙Bluetooth﹚，802.11﹙Wi-Fi﹚，ZigBee和超寬頻系統，因此不論是學術上的研究或者是工業上的發展，此類的電路系統己成為現今研究發展的主流。
本論文在此提出一個相關的電路應用於超寬頻無線通訊系統，此電路為可變增益放大器，其電路主要由三個子電路所構成，分別為主放大器，增益控制電路，及共模回授電路；而主放大器是運用一個摺疊疊接放大器與一個回授電路所構成，增益控制電路則是利用一個簡單的源耦合對來達到控制增益大小之能力。而本電路是利用TSMC 0.18um 製程參數進行設計與模擬，並且運用改良式的虛擬指數方程式來實現其可變增益之功能並提高線性度甚至透過一個控制訊號能達到改變其增益調變之範圍。模擬之結果顯示輸出增益範圍可從-7.16dB至11.3dB，將近18dB。在最大輸出增益時的操作頻率為610MHz ，此頻率已符合超寬頻系統之規格且在1.8v的供應電壓下所得到的消耗功率低於2mW。

關鍵字

可變增益放大器 ； 虛擬指數可變增益放大器 ； 超寬頻

並列摘要

The booming development of the wireless communication technology in recent years make the relevant products, such as GSM, CDMA, Bluetooth, 802.11 (Wi-Fi), ZigBee and Ultra wide band (UWB) widely used in our daily life and became important research topics.
This thesis proposes a Variable Gain Amplifier (VGA) that is suitable for UWB system. It consists of a main amplifier, gain control circuit, and a common mode feedback loop. The main amplifier is realized by a folded cascode amplifier with feedback and the gain control function is utilized by a source-coupled pair to realize controllable gain. A modified pseudo-exponential equation is proposed to improve the linearity of the proposed VGA. The circuit is designed and simulated in TSMC 0.18um CMOS process. The gain range of 18dB and the 3dB frequency of 610MHz at the maximum gain that meets the specification of UWB system is obtained. The power dissipation is less then 2mW at 1.8V supply voltage.

並列關鍵字

pseudo-exponential VGA ； Variable gain amplifier ； UWB

參考文獻

[1] M. Bathaee, H. Ghezalayagh, Wang Qin Heng, D. Nicolae, O. Fratu, R. Pop, G. Dilimot, V. Feies, P. Agache, R. Ruscu, M. Iorgulescu, Jing Gang, Wei Mao Lin, Ma Lei, Dong Zhao Hui, and Wang Tao, “A 0.13 um CMOS SoC for all format blue and red laser DVD front-end digital signal processor,” in IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, pp. 1012 – 1021, Feb 2006.

[2] Yong-Sik Youn, Cheon-Soo Kim, Nam-Soo Kim, and Hyun-Kyu Yu, “A 1 GHz-band low distortion up-converter with a linear in dB control VGA for digital TV tuner,” in Symp. IEEE Radio Frequency Integrated Circuits (RFIC) Papers, pp. 257 – 260, May 2001.

[3] Jie-Wei Lai, Yu-Ju Chuang, K. Cimino, and Milton Feng, “Design of variable gain amplifier with gain-bandwidth product up to 354 GHz implemented in InP-InGaAs DHBT technology,” in IEEE Trans. Microwave Theory and Techniques, Vol. 54, pp. 599 – 607, Feb. 2006.

[4] R. Harjani, “A low-power CMOS VGA for 50 Mb/s disk drive read channels,” IEEE Trans. Circuits Syst. II, Vol. 42, pp. 370 – 376, June 1995.

[5] Yuanjin Zheng, Jiangnan Yan, and Yong Ping Xu, “A CMOS dB-linear VGA with pre-distortion compensation for wireless communication applications,” in Symp. ISCAS. Vol. 1, pp. 813 – 816, May 2004.