João Batista Vieira

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—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)
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)
High power factor, high frequency single stage single switch resonant inverter for the application of high frequency applications is presented in this paper. The power circuit is designed with a power factor corrector with single-switch current-fed high frequency resonant inverter. Number of switches used in conventional ballast circuits is reduced in(More)
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