1,722,943 research outputs found
On the use of Magnetically Coupled Resonant Snubbers to Mitigate the Electromagnetic Emission of Power Switching Circuits
Full text linkThis letter presents a novel solution to attenuate the electromagnetic emission of power switching circuits due to the resonance of the loop parasitic inductances with the parasitic capacitances of the power devices. A resonant snubber based on the magnetic coupling of a power parasitic loop causing unwanted oscillations with another one inserted at the printed circuit board level purposely and loaded by a dissipative element, is presented. A design method is proposed and used to damp the unwanted oscillations affecting the switching voltage and current in a prototype, which was specifically designed and fabricated to validate the proposed solution. The conducted emission delivered by such a prototype equipped with the resonant snubber, with an RC snubber, and without any snubber are compared
Susceptibility to Radio Frequency Interference of eGaN Power Switching Legs
Full text linkPower switching circuits like those used in inverters
and DC-DC converters are usually investigated with the purpose
of increasing the power efficiency or lowering the electromagnetic
emissions. Considered that, the reliability of such modules is
also a key aspect, especially in safety critical applications, this
work focuses on the susceptibility of such circuits to radio
frequency interference. To this purpose, an e-mode GaN power
switching leg in a real application environment is considered. A
circuit comprising the nominal active and passive components,
their stray inductances and capacitances as well as those due
to the PCB wiring is presented. The effect of radio frequency
interference injected into the output terminal by means of a
bulk current injection clamp is analyzed with the purpose of
evaluating the risk that such interference propagated through
the circuit could induce temporary or permanent failures
A new current sensor based on the Miller effect highly immune to EMI
No full textThis paper deals with the susceptibility to electromagnetic interference (EMI) of circuits used in smart power integrated circuits to sense the current of power transistors. The susceptibility of a conventional current sensor based on the mirroring principle is first investigated. Then a new circuit that avoids the electrical connection of the current sensor to the power transistor drain terminal is proposed. The susceptibility of the above mentioned current sensors is discussed and evaluated by means of time-domain computer simulations. © 2012 IEEE
Experimental investigations on the tuning of active gate drivers under load current variations
Full text linkActive Gate Drivers have gained of interest as they allow one to shape the switching waveforms finely, thus reducing overshoots and oscillations. However, when fast power switches are exploited, the tuning of such drivers is still challenging. This paper investigates the adjustment of gate current profile under load variations, which is a crucial issue when targeting practical applications. Indeed, a technique, based on the stretching of time intervals, is proposed and its effectiveness, in terms of undershoot reduction, is experimentally assessed
A new MagFET-based integrated current sensor highly immune to EMI
No full textThis paper deals with the susceptibility to radio frequency interference of the integrated circuits used to monitor the current of power devices. A circuit based on the mirroring principle of common use in commercial devices is first considered, then a new contact-less fully integrated current sensor based on the Hall effect is proposed. The design of this current sensor is shown in detail and its susceptibility to radio frequency interference is investigated through time-domain simulations. The results of these analyses are presented then compared with those obtained from similar analysis carried out on a conventional (wired) current sensor. © 2012 Elsevier Ltd. All rights reserved
Decimation of Delta-Sigma-Modulated Signals Using a Low-Cost Microcontroller
Full text linkΔΣ analog-to-digital converters (ADCs) are largely used in sensor acquisition applications. In the last few years, standalone ΔΣ modulators have become increasingly available as off-the-shelf parts. To build a complete ADC, a standalone modulator has to be paired with some advanced elaboration unit, such as a field programmable gate array (FPGA) or a digital signal processor (DSP), which is needed for the implementation of the decimation filter. This work investigates the use of low-cost, general-purpose microcontrollers for the decimation of ΔΣ-modulated signals. The main challenge is given by the clock frequency of the modulator, which can be in the range of a few MHz. The proposed technique deals with this limitation by employing two serial peripheral interface (SPI) modules in a time-interleaved configuration. This approach allows for continuous acquisition and elaboration of relatively high-speed, digital signals. The technique has been applied to a case study, and a data conversion system has been practically realized. The performance of the proposed filter is compared to that of a digital filter, present on board a commercial microcontroller, and the results of experimental tests are provided
A new mirroring circuit for power MOS current sensing highly immune to EMI
No full textThis paper deals with the monitoring of power transistor current subjected to radio-frequency interference. In particular, a new current sensor with no connection to the power transistor drain and with improved performance with respect to the existing current-sensing schemes is presented. The operation of the above mentioned current sensor is discussed referring to time-domain computer simulations. The susceptibility of the proposed circuit to radio-frequency interference is evaluated through time-domain computer simulations and the results are compared with those obtained for a conventional integrated current sensor. © 2013 by the authors; licensee MDPI, Basel, Switzerland
Current sensing circuit for DC-DC converters based on the miller effect
No full textThis paper deals with the inductor-current monitoring for switching regulators. Conventional current sensors based on the mirroring principle are first considerated. Then, a new circuit that reaches improved performance respect to the existing current-sensing schemes is proposed. The operation of the above mentioned current sensors are discussed and evaluated by means of time-domain computer simulations. © 2013 University of West Bohemia
Laparoendoscopic extraperitoneal surgical techniques for ventral hernias and diastasis recti repair: a systematic review
Full text linkPurposethis systematic review aims to classify and summarize the characteristics and outcomes of the different laparoendoscopic extraperitoneal approaches for the repair of ventral hernias and diastasis recti described in the last 10 years.Methodsa literature search was performed by two reviewers in December 2023 including articles from January 2013, 01 to December 2023, 15. The techniques were selected according to the surgical access site (anterior or posterior to the rectus sheath), the access type (laparoendoscopic, single incision laparoscopic, mini or less open), the main space used to repair the defect (subcutaneous or retromuscular) and the mesh place (onlay, sublay-retromuscular or sublay-preperitoneal) and classified as anterior or posterior approaches.Resultsthe literature search retrieved 1755 results and 27 articles were included in the study. The studies included 1874 patients, the mean age ranged from 37.8 to 60.2 years. The access site was anterior in 16 cases and posterior in 11 cases. The mesh was positioned onlay in 13 cases and sublay in 13 cases, with only one study using no mesh. Complications were: seroma, ranging from 0.8 to 81%, followed by skin complications (leak, ischemia, necrosis) from 0.8 to 6.4%, surgical site infections and bleeding. Recurrences ranged from 0% to 12,5%, with a mean follow-up from 1 to 24 months.Conclusionthis systematic review confirms the presence of several new minimally invasive extraperitoneal techniques for the repair of abdominal wall defects, with different advantages and disadvantages. Further studies, with more extensive follow-up data and wider patient groups, are necessary to define specific indications for each technique
A new current sensor based on MagFET highly immune to EMI
No full textThis paper deals with the susceptibility to electromagnetic interference of CMOS integrated current sensors for power transistor current monitoring. Conventional integrated solution are first considered, hence a new integrated current sensor based on the Hall effect in MOS transistors (MagFET) is proposed. The susceptibility to radio frequency interference of a conventional (wired) current sensor and that of the MagFET-based solution is discussed. © 2009 IEEE
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