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A current reference is able to provide a precise and accurate current for other circuits inside a chip. This type of electronic circuit is employed as a building block in numerous analog and mixed-signal circuits. Moreover, it is a fundamental component of current-mode circuits. This work discusses the basic and essential concepts of designing CMOS integrated current references. A review of conventional topologies is presented, including current mirrors and current references. Temperature dependence is discussed, along with PTAT and CTAT topologies, and some low-power/low-voltage implementations are also presented.

Background: Bladder cancer (BCa) is a heterogeneous disease with a variable prognosis and natural history. Cardiovascular disease (CVD), although completely different, has several similarities and possible interactions with cancer. The association between them is still unknown, but common risk factors between the two suggest a shared biology. Materials and Methods: This was a retrospective study that included patients who underwent transurethral resection of bladder tumor at two high-volume institutions. Depending on the presence of a previous history of CVD or not, patients were divided into two groups. Results: A total of 2050 patients were included, and 1638 (81.3%) were diagnosed with bladder cancer. Regarding comorbidities, the most common were hypertension (59.9%), cardiovascular disease (23.4%) and diabetes (22.4%). At univariate analysis, independent risk factors for bladder cancer were age and male sex, while protective factors were cessation of smoking and presence of CVD. All these results, except for ex-smoker status, were confirmed at the multivariate analysis. Another analysis was performed for patients with high-risk bladder cancer and, in this case, the role of CVD was not statistically significant. Conclusions: Our study pointed out a positive association between CVD and BCa incidence; CVD was an independent protective factor for BCa. This effect was not confirmed for high-risk tumors. Several biological and genomics mechanisms clearly contribute to the onset of both diseases, suggesting a possible shared disease pathway and highlighting the complex interplay of cancer and CVD. CVD treatment can involve different drugs with a possible effect on cancer incidence, but, to date, findings are still inconclusive.

A novel Type-Reduction/Defuzzification circuit architecture for an analog interval type-2 fuzzy inference system is proposed. Based on the Nie-Tan type-reduction method, the circuit operates with current-mode inputs, representing the firing intervals of the rules created by the inference engine, and generating a PWM output. It is demonstrated that by selecting an appropriate number of consequents it is possible to create the PWM output directly, without the need for analog multiplier/divider circuits. This feature makes the circuit very simple, aiding in the design process, while the PWM output makes it suitable for controlling DC-DC converters, maximum power point trackers (MPPT) for energy generators, or other switching applications. It is designed to achieve very low power consumption, allowing its use in power restrained environments, such as energy harvesting systems. The circuit was designed using TSMC $0.18~\mu \text{m}$ technology, in CADENCE Virtuoso software, and simulated for different combinations of input values, demonstrating its capabilities. It was also simulated as part of a type-2 fuzzy inference system with two inputs, nine rules, and firing intervals represented by currents within 0 and $10~\mu \text{A}$ . The circuit was prototyped, and the experimental average power consumption was only $53.8~\mu \text{W}$ , validating its low power consumption characteristic.

A novel strategy for implementation of an analog current-mode interval type-2 fuzzy inference engine circuit with low-power consumption is presented. Previous current-mode architectures rely on minimum/maximum circuits, using current mirrors to perform bounded-difference operations or winner-take-all circuits to mirror the appropriate current among the inputs. It means that currents representing the membership degrees of input fuzzy sets may need to be copied several times to obtain the firing levels of each rule. To avoid this drawback, the proposed method uses high-gain differential amplifiers, operating with low bias currents, as comparators, creating digital signals that indicate the largest/smallest current. It allows digital gates to determine directly which of the currents from the membership degree generator circuits represent the correct solution to the overall inference process. The methodology for developing the system and obtaining the logical expressions is presented. Simulations show that a traditional implementation using min/max circuits presented in the literature consumes 4.4 times more power than the proposed architecture. The circuit was prototyped in TSMC 0.18- $\mu \text{m}$ technology and its functionality demonstrated by the correct generation of the consequents firing levels. The measured power consumption was 413.42 $\mu \text{W}$ , including the power from the fuzzifier circuits, with a power supply of 1.2 V.

Made available in DSpace on 2018-11-26T15:46:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) A novel analog fuzzy membership function generator architecture, based on current steering mirrors, for interval type-2 fuzzy controllers is proposed in this paper. The Footprint of Uncertainty (FOU), characteristic of an interval type-2 fuzzy set, is generated by this novel architecture, which uses current steering mirrors controlled by a voltage input and allows width variation based on a central line. This main feature makes the circuit inherently type-2, i.e., not dependent of any type-1 fuzzifier, unlike all previous analog fuzzifiers found in the literature. The circuit operates in current mode and is capable of generating trapezoidal, triangular, Z-shaped and S-shaped membership functions. Input currents allow shape configuration, whereas a digitally programmable current mirror provides different inclinations, making it fully programmable (shape, width of the FOU, inclination, and position). Simulations validating the architecture were performed with TSMC CMOS 0.18 mu m technology, in CADENCE software. The circuit was later fabricated and characterized. Experimental results confirmed its ability to work as a fuzzifier, with all specified features, showing to be suitable even for dedicated low power applications. Inst Tecnol Aeronaut, Dept Eletron Aplicada, Praca Marechal Eduardo Gomes 50, BR-12228900 Sao Jose Dos Campos, SP, Brazil Univ Estadual Paulista, UNESP, Dept Engn Eletr, Campus Guaratingueta,Ave Ariberto Pereira da Cunha, BR-12516410 Guaratingueta, SP, Brazil Univ Estadual Paulista, UNESP, Dept Engn Eletr, Campus Guaratingueta,Ave Ariberto Pereira da Cunha, BR-12516410 Guaratingueta, SP, Brazil

Il saggio riflette sulla categoria dell'invenzione della tradizione introdotta Da E.J. Hobsbawm e T.O. Ranger e analizza alcuni aspetti dell'uso contemporaneo del passato.