This 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.

The Indoor Environmental Quality (IEQ) combines thermal, visual, acoustic, and air-quality conditions in indoor environments and affects occupants’ health, well-being, and comfort. Performing continuous monitoring to assess IEQ is increasingly proving to be important, also due to the large amount of time that people spend in closed spaces. In the present study, the design, development, and metrological characterization of a low-cost multi-sensor device is presented. The device is part of a wider system, hereafter referred to as PROMET&O (PROactive Monitoring for indoor EnvironmenTal quality & cOmfort), that also includes a questionnaire for the collection of occupants’ feedback on comfort perception and a dashboard to show end users all monitored data. The PROMET&O multi-sensor monitors the quality conditions of indoor environments thanks to a set of low-cost sensors that measure air temperature, relative humidity, illuminance, sound pressure level, carbon monoxide, carbon dioxide, nitrogen dioxide, particulate matter, volatile organic compounds, and formaldehyde. The device architecture is described, and the design criteria related to measurement requirements are highlighted. Particular attention is paid to the calibration of the device to ensure the metrological traceability of the measurements. Calibration procedures, based on the comparison to reference standards and following commonly employed or ad hoc developed technical procedures, were defined and applied to the bare sensors of air temperature and relative humidity, carbon dioxide, illuminance, sound pressure level, particulate matter, and formaldehyde. The next calibration phase in the laboratory will be aimed at analyzing the mutual influences of the assembled multi-sensor hardware components and refining the calibration functions.

Electromagnetic emissions (EME) of electric and electronic units should comply with national and international standards. Software approaches to reduce the conducted EME are preferable, since they do not require additional on-board hardware. Many techniques have been developed, with different levels of efficiency. This work aims to analyze a new software method to mitigate the conducted emissions of three phase power inverters, focusing on those used to drive brushless DC motors (BLDC). This has been done reducing the conducted EMI common mode (CM) component using software to compensate parasitic delays. The technique is verified both analytically and experimentally, and its performances have been compared to the Spread Spectrum Modulation (SSM) ones. The proposed approach shows better performances with respect to SSM below 24 MHz. The results confirm the effectiveness of the delay compensation technique in terms of CM conducted emissions reduction. Moreover, the proposed approach has no drawbacks on safety and it does not present reductions in the inverter efficiency.

Effective electromagnetic interference (EMI) filters are required by switching converters to comply with conducted emission regulations. However, these filters often pose significant challenges, being expensive, bulky, and heavy. Such an issue is further aggravated with the latest generation of wide band gap (WBG)-based power converters. Reduction of the filter size can be achieved through conducted EMI mitigation techniques that address emissions at the source, particularly at low frequencies. Spread-spectrum modulation (SSM) has gained increasing interest to mitigate EMI, as it does not require any hardware alterations. This article investigates the effectiveness of the SSM in case of WBG traction inverters, where the switching frequency remains in the tens of kilohertz. In addition, the use of an additional switching leg to reduce the EMI was also investigated. A comparative analysis of these two techniques and their effectiveness in the common mode (CM) conducted EMI suppression is carried out. Experimental results are provided demonstrating the feasible CM conducted EMI reduction. It was found that the EMI peak at 160 kHz decreased by 2 dB in the SSM case and by 25 dB in the additional leg case.

This paper deals with the susceptibility to RF interference of a temperature sensor used in smart power system-on-chip to shut down the source of heat or the overall device in the case of overtemperature. Such a sensor is usually buried within the power section; hence, it is parasitically coupled with the power transistors and for this reason its operation can be affected by the disturbances superimposed onto the power transistors' nominal signals. In this work, the detrimental effect of the RF interference on a common thermal shutdown circuit is analyzed using an approximate nonlinear model and performing time-domain computer simulations. The results of these analyses show that RF interference can induce false fault signaling. To avoid this, a simple and effective layout solution that improves the immunity of such kind of circuits is proposed and its effectiveness is proved by experimental test results.

The continuous trend toward the miniaturization of modules, comprising high sensitive devices along with noisy circuits like wireless transceivers and digital core blocks, has led us to investigate the effect of disturbances on analog front-end circuits used in system-in-package modules. In this context, this paper focuses on the distortion of radio frequency interference in CMOS current feedback instrumentation amplifiers like those used in MEMS readout circuits. The way baseband signals are distorted by such amplifiers, when the interference is superimposed onto the input signals, is analyzed referring to a math model, to computer simulations and to measurements carried out on a test chip designed and fabricated specifically for this purpose.