A 34µW 75dB-dynamic-range CMOS analog front-end for intelligent tyre sensor network

A high performance analog front-end for intelligent tyre MEMS accelerometer sensor is presented in this paper. The analog front-end is part of a bigger System-On-Chip totally integrated inside the car tyre, with the aim to interchange real time data with the car central unit. Such system is intrinsically self-biased (a vibration-based scavenger device is used), so that a very low power budget is available for the analog front-end (<;100μW). Constant-charge capacitance-to-voltage conversion has been used for readout input acceleration sensing, that allows to reduce power and circuital complexity. At the same time large Signal-To-Noise-Ratio (>75dB over 1Hz÷4kHz bandwidth) has been obtained by a simple in-band noise filtering, while maintaining pass-band frequency response for the acceleration readout input signal. A prototype of the accelerometer analog front-end has been designed in CMOS 0.13μm technology node. The overall readout power consumption is 34μW, from a single 1.2V supply voltage.