Ultra-low-power compressive-readout integrated circuit design for smart and wearable biosensing

This work presents the design of an ultra-low-power compressive-readout integrated circuit (IC) for amperometric electrochemical sensors. The application-specific integrated circuit (ASIC) has been designed in the frame of a project that aims to develop non-invasive integrated wearable platforms for monitoring the sweat of athletes in real time. The ASIC, which will be part of the sensing platforms, must be able to measure full scale currents in the order of µA with resolutions in the order of nA, while consuming a µW-range power in order to provide the wearable platform with enough energy autonomy. Moreover, the ASIC must include a digital communication interface for a reliable data transmission. The amperometric sensor frontend, designed following a full-custom analog IC design methodology, has been realized with a 3-quantization-level asynchronous delta-sigma (∆Σ) modulator topology. The inclusion of the sensor in the ∆Σ loop has resulted in a compact architecture. The digital communication backend, designed following a semi-custom digital IC design flow, has been developed by adapting a serial communication protocol and modifying it to allow an asynchronous communication of data, which results in an increase of the power efficiency. To conclude the work, these two blocks have been integrated in a 0.18-µm complementary metal-oxide-semiconductor (CMOS) technology