A Self-Actuated Front-End for Resonating Sensors

In this work, we propose a novel self-actuated analog front-end (AFE) for resonating sensors, realized in pseudo floating gate technology. The core of the analog front-end is based on a re-configurable circuit, which works as a SRAM cell when the resonating sensor must be actuated and behaves as a pseudo floating gate amplifier (PFGA) when the sensor response must be read-out. The timing for the actuation/readout cycle is provided by an inverter based control system, which is connected with the AFE in a positive feedback loop. The use of solely inverter logic gates to implement the whole system simplifies the design of the circuit, minimizes the occupied area, and makes possible to use the proposed system in low voltage applications (VDD < 3.3V). The operation of the proposed circuit has been verified by simulations in AMS-350nm CMOS technology with a power supply of 3.3V. At the end of this paper, the effects of process, temperature and power supply (PVT) variations have been investigated, and a few solutions to compensate these side effects have been proposed. Finally, the average power consumption of the circuit has been measured to be 445µW, which is in the same order of other front-ends described in literature.