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The Research Based On Log-domain Current-mode Filters

Posted on:2007-06-29Degree:MasterType:Thesis
Country:ChinaCandidate:S J LuoFull Text:PDF
GTID:2178360185980825Subject:Power electronics and electric drive
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The log-domain filter is one of the technologies which aims to low voltage, low power and large dynamic range design. It takes advantage of the exponential I-V characteristics of the active devices such as bipolar junction transistor (BJT), compressing the dynamic range of the input signal and reducing internal voltage amplitudes, it can maintain large dynamic range and high operating frequency under low supply voltage, the main area of application for this technique is the implementation of continuous-time fully integrated filters (or circuits) with low voltage wide dynamic range, high-frequency, and wide tenability.The dissertation has studied the structure designs, methods, applications of log-domain filers, and derived several practical synthesis methods of log-domain filters. The innovative points of this dissertation include:1.Designing of second-order log-domain current-mode filters based on the simulation of OTA-C. The method can use the experience of OTA-C, and convert the OTA-C filters to its log-domain forms. The proposed filters have simple structure, and are suitable for the low power supply. The circuits are composed of bipolar transistors and grounded capacitors which make them suitable for the fully-integrated circuit implementation.2.A universal way to design any order log-domain current-mode filters based on signal flow graph is present. From the transfer function of the system, and transform the signal flow graph to its log-domain form, then use the corresponding log-domain circuit to realize the log-domain filtering. The method is generic and especially can be applied to the design of high order log-domain filters.3.Filter based on multi-input CMOS differential log-domain integrator is presented. Filter design on the CMOS differential log-domain integrator can effectively eliminate the double harmonious and reduce the distortion. The characteristic of multi-input is convenient to the design of the filter. The structure is simple and compatible to MOS technology.4.The filter design based on the log-domain differentiator. A second order high-pass and band-pass log-domain filter is designed based on the differentiator, its cut-off frequency and quality factor can be tuned through the bias current, and is easy to cascade to realize high order filter.
Keywords/Search Tags:log-domain, current-mode, continuous time filter
PDF Full Text Request
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