Low-power pressure sensor front-end for implantable passive RFID tags

In this paper, a pressure sensor interface circuit for implantable passive high frequency radio frequency identification (RFID) tag is designed. On one hand, in order to meet the requirements of small input swing and low power consumption, an internal programmable amplifier is designed to fix the floating common-mode voltage of the external pressure sensor and process the tiny pressure fluctuation signal generated by human body. On the other hand, in order to solve the problem that traditional passive RFID sensors sacrifice sampling accuracy for low power consumption, a two-order discrete sigma-delta analog-to-digital converter (ADC) is proposed in this paper. Using UMC180nm process and 1.8V power supply voltage, the sampling accuracy reaches 15.68bit. The total power consumption is only 71.6uW with an area of only 0.0768mm
²
.