A 2-D wind sensor, based on microelectromechanical systems (MEMS) flow sensors, is presented. The device consists of a cylinder with a channel network connecting the internal flow sensors with the lateral surface. The pressure distribution developed by the wind on the cylinder's surface is thus converted into two air flows from which, due to the special channel configuration, wind speed and direction can be unequivocally determined. Since the MEMS devices are located in the channels, their fragile sensing structures are protected from direct exposure to the wind. Performance estimation based on literature data of pressure distributions indicates that the approach is applicable to a wide wind velocity range. The feasibility of the idea is supported by measurements performed on a prototype.

A capacitance-to-pulse duration converter, specifically designed for interfacing capacitive sensors, is presented. The operating principle is a double slope approach implemented using transconductor-based Miller integrators. The main strengths of the proposed circuit are: 1) intrinsically small sensitivity to temperature; 2) simplicity of trimming offset and gain to correct the sensor parameter spread; and 3) fast wake-up time. The circuit nonidealities are analyzed in order to identify the elements responsible for the residual temperature sensitivity and jitter on the pulse duration. The effectiveness of the method is demonstrated by measurements performed on a prototype, designed and fabricated using the 0.35 mum, 3.3 V Bipolar-CMOS-DMOS process BCD6 of STMicroelectronics.

This work presents a single-stage, inverter-based, pseudo-differential amplifier that can work with ultra-low supply voltages. A novel common-mode stabilization loop allows proper differential operations, without impacting over the output differential performance. Electrical simulations show the effectiveness of this amplifier for supply voltages in the range of 0.3–0.5 V. In particular, a dc voltage gain of 25.16 dB, a gain-bandwidth product of 131.9 kHz with a capacitive load of 10 pF, and a static current consumption of only 557 nA are estimated at V_DD = 0.5 V. Moreover, the circuit behavior with respect to process and temperature variations was verified. Finally, the proposed amplifier is employed in a switched-capacitor integrator and in a sample-and-hold circuit to prove its functionality in case-study applications.