João Batista Vieira

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This paper presents an improved regenerative soft turn-on and turn-off snubber applied to a boost pulsewidth-modulated (PWM) converter. The boost soft-single-switched converter proposed, which has only a single active switch, is able to operate with soft switching in a PWM way without high voltage and current stresses. This is achieved by using an auxiliary(More)
This paper presents a quadratic boost converter using a single quasi-resonant network to reach soft commutation. A resonant inductor, a resonant capacitor, and an auxiliary switch form the resonant network and the main switch operates in a zero-current-switching way. A complete analysis of this converter is presented. According to the simulation and(More)
High switching frequency associated with soft commutation techniques is a new trend in switching converters. Following this trend, the authors present a buck pulsewidth modulation converter, where the dc voltage conversion ratio has a quadratic dependence on duty cycle, providing a large step-down. By introducing two resonant networks, soft switching is(More)
One of the most interesting areas for researchers in<lb>power electronics is the use of microprocessor circuits replacing the<lb>existent analog circuits employed in converter control. Due to the increasing progress in microprocessor<lb>circuitry, there have been high technology components available that<lb>are perfectly suitable to converter control. The(More)
The prevalence of ocular lesions due to onchocerciasis was evaluated among residents of the Yanomami Tribe, in the northern Amazon, Brazil, an endemic area for onchocerciasis. 83 natives were submitted to an ocular examination including an external examination, biomicroscopy, intraocular pressure measurement, and a fundus examination. Clinical,(More)
Paresthesia is defined as an alteration in local sensibility, associated with numbness, tingling, or unpleasant sensations caused by nerve lesions or irritation. It can be temporary or permanent. The treatment protocol for facial paresthesia is primarily based on the use of drugs and implant removal, which may not be completely effective or may require(More)
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