Design of Current-Mode High-Order OTA-C and CCCII-C MISOC Filter Structures

• Main Authors: Jin-Rui Tsai, 蔡金叡
• Other Authors: Chun-Li Ho
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/97269599494229029487

碩士 === 中原大學 === 電機工程研究所 === 92 === In recent one and a half decades, the current-mode circuit is proved to be much more precise than its voltage-mode counter part. Since the transconductance of an operational transconductance amplifier (OTA) and the inner intrinsic resistance at terminal x of a second-generation current controlled conveyor (CCCII) are electronically adjusted by the internal bias current, no resistors in the OTA-C or CCCII-C circuit become an important advantage in the active filter design. In the thesis, the current-mode high order OTA-C and CCCII-C MISOC (multi-input single-output circuit) structures are presented. The least number of active and passive elements, N, for n-th order filters is used in the design. Because all of the active and passive elements are grounded, it is attractive for integration and reduces the effect of parasitic capacitors. In the beginning, two powerful active elements, CCCIIs and OTAs, are introduced. Two circuit design approaches, signal-flow-graph and the use of building block, are used in the thesis. Then a multi-input and single-output circuit structure is successfully developed to realize the current-mode high-order universal (i.e., high-pass, low-pass, band-pass, band-reject and all-pass) filters. The proposed filter structure is implemented by the OTA-C or CCCII-C circuits. H-Spice simulation with TSMC025 parameter process validates the theory predictions for both OTA-C and CCCII-C circuit implementations, although the former is more precise in high frequency performance than the latter.