Browsing by Author "Morais, Raul"
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- A 1.2V 900nW conductance converterPublication . Miranda, Nuno; Morais, RaulThis article describes a new electrical conductance converter method suitable for very low power applications, where energy constraints prevails over speed and measurement accuracy. Method idea gather voltage time integration and shopper stabilization techniques to process noisy low amplitude signals and to overcome severe limitations of weak inversion channel CMOS circuitry. Main features and tradeoffs are exploited. A 1.2V ASIC implementation on standard 0.35μm CMOS schematics is also presented. Post-layout simulations shows a total power consumption lower than 900nW including current source excitation inherent to the conductance measurement. Such low power consumption allows the measurement of several physical parameters on self-powered wireless networks.
- Sensing methodologies to determine automotive damper condition under vehicle normal operationPublication . Ferreira, Carlos Daniel Henriques; Ventura, Paulo; Morais, Raul; Valente, António L.G.; Neves, Carlos; Reis, Manuel C.Vehicles rely on the efficiency of dampers to dissipate energy from the motion of vehicle body and wheels, maintaining the vehicle more stable, and improving the contact between tires and the road surface. To achieve an effective monitoring of dampers (or shock absorbers), two different methodologies, capable of assessing, under vehicle normal operation, the condition of the automotive dampers are presented. The proposed methodologies are based in acceleration, temperature and pressure sensing to determine the shock absorber condition, and are therefore suitable for future implementation in low cost fabrication technologies. The results shown that it is possible to have an effective monitoring device, installed in the damper body, capable of continuously determining shock absorber status, and therefore enabling real time diagnosis. Such a diagnosis system can reduce the number of vehicles riding with defective suspension systems and increase the overall vehicle safety.