A Multi-Output Multi-String High-Efficiency WLED Driver Using 40 nm CMOS Technology

In this work, a multi-independent-output, multi-string, high-efficiency, boost-converter-based white LED (WLED) driver architecture is proposed. It utilizes a single inductor main switch with a common maximum duty cycle controller (MDCC) in the feedback loop. A simple pulse skipping controller (PSC) is utilized in each high-side switch of the multiple independent outputs. Despite the presence of multiple independent outputs, a single over-voltage protection (OVP) circuit is used at the output to protect the circuit from any voltage above 27 V. An open circuit in any of the strings is addressed, in addition to the LED’s short-circuit conditions. Excellent current matching between strings is achieved, despite the low ON-resistance (Rdson) of transistors used in the 40 nm process. Most circuits are designed in digital CMOS logic to overcome the extreme process variations in the 40 nm node. Compared to a single output parallel strings topology, a 50% improvement in efficiency is achieved relative to extremely unbalanced strings. Three strings are used in this proposal, but more strings can be supported with the same topology. Each string is driven by a 25 mA current sink. An input voltage of 3.2–4.2 V and an output voltage up to 27 V are supported.

Avaliação da ocorrência de sinusopatias em radiografia panorâmica de uma clínica-escola do extremo sul de Santa Catarina

Objetivo: Avaliar a ocorrência de sinusopatias em 1095 pacientes que realizaram radiografias panorâmicas em uma clínica-escola do extremo sul catarinense, atendidos entre 2014 e o primeiro semestre de 2019. Método: O presente trabalho refere-se a uma pesquisa quantitativa, retrospectiva, descritiva, documental e de campo. Todas as radiografias panorâmicas digitais presentes neste estudo foram realizadas por um equipamento Eagle (Dabi Atlante, SP, Brasil) com fatores radiográficos de aproximadamente 70 kV e 10 mA, ajustados de acordo com critérios individuais de cada caso, com tempo de exposição de 13 segundos e com uso do sensor digital CMOS. As imagens foram avaliadas por um cirurgião-dentista especialista em radiologia odontológica. Resultados: A pesquisa foi constituída majoritariamente por pacientes do sexo feminino de faixa etária adulta. Resultou-se que, das radiografias panorâmicas avaliadas nesta pesquisa, 35,8% apresentaram alterações em seios maxilares e as sinusopatias mais encontradas foram pseudocisto de retenção e sinusite crônica. Não houve relevância estatística entre as alterações encontradas em relação à idade ou ao gênero. Conclusão: A radiografia panorâmica é um exame complementar de ampla utilização na área odontológica que pode permitir a identificação de alterações nos seios maxilares, no entanto, quando há sinusopatias, deve ser associada ao exame clínico para correto diagnóstico.

NANO-studio, the design environment of filter banks implemented in standard CMOS technology

The paper presents a method of optimizing frequency characteristics of filter banks in terms of their implementation in digital CMOS technologies in nanoscale. Usability of such filters is demonstrated by frequency-interleaved (FI) analog-to-digital converters (ADC). An analysis filter present in these converters was designed in switched-current technique. However, due to huge technological pitch of standard digital CMOS process in nanoscale, its characteristics substantially deviate from the required ones. NANO-studio environment presented in the paper allows adjustment, with transistor channel sizes as optimization parameters. The same environment is used at designing a digital synthesis filter, whereas optimization parameters are input and output conductances, gyration transconductances and capacitances of a prototype circuit. Transition between analog s and digital z domains is done by means of bilinear transformation. Assuming a lossless gyrator-capacitor (gC) multiport network as a prototype circuit, both for analysis and synthesis filter banks in FI ADC, is an implementation of the strategy to design filters with low sensitivity to parameter changes. An additional advantage is designing the synthesis filter as stable infinite impulse response (IIR) instead of commonly used finite impulse response (FIR) filters. It provides several dozen-fold saving in the number of applied multipliers.. The analysis and synthesis filters in FI ADC are implemented as filter pairs. An additional example of three-filter bank demonstrates versatility of NANO-studio software.

MEASURING AND MODELING THE EFFECT OF LOW INTENSITY RADIATION ON DIGITAL CMOS ICS

Based on the results of measuring the characteristics of CMOS ICs in the dose range up to 0.5 Mrad with an intensity of 0.1 rad / s, the changes in the concentration of defects Nit, Not were calculated, and the parameters of SPICE models of MOS transistors IC were identified. Circuitry modeling made it possible to estimate the critical value of the dose for the degradation of the parameters of the studied ICs.