128 nodes 4.5 mm pitch 15-bit pressure sensor ribbon

Abstract

This paper presents a high density pressure measurement ribbon used to characterize air-flow on a shape. The system is made of 128 15-bits pressure sensors thermally compensated by 10 bits temperature sensors. The MEMS pressure sensor capacitance variations are converted into digital thanks to a second order switched capacitors sigma-delta converter. An innovative serial-bit sliding window FIR filter allows asynchronous data transfer on the 8MHz SPI like bus with limited time response (<;1ms) and low frequency modulator (333kHz). The temperature to digital conversion is carried out by a passive sigma-delta modulator, reaching low area and low power consumption. The global system noise is limited to 24 Pa in a range of [20kPa/95kPa] and [-30°C/+60°C].