DAPPER: A Low Power, Dual Amperometric and Potentiometric Single-Channel Front End

Abstract

DAPPER is a front end system capable of simultaneous amperometric and potentiometric sensing proposed for lowpower multi-parameter analysis of bio-fluids such as saliva. The system consists of two oscillator circuits, generating a frequency relative to their sensed current and voltage signals. These signals are then mixed together to produce a single channel output that can be transmitted through backscattering (load-shift keying). The entire system consumes 40µW from a 1.4V supply. The linear ranges of potentiometry and amperometry circuits are 0.4V -1V and 250pA -5.6µA (87dB), and their input referred noise is 1.7µV and 44.6fA, respectively.

SPACEMan: Wireless SoC for Concurrent Potentiometry and Amperometry

“…The switched capacitor integrator and the comparator in a feedback loop converts this current into a frequency range of 400Hz -400kHz. This circuit is an optimised form of [13] with a lower power consumption of 62% lower power at the cost of reducing input current range from the previous 250pA -5.6µA range to 80pA -1µA.…”

“…A system-on-chip, 3×3mm sized, for multiple applications in sweat and saliva analysis or point-of-care diagnostics amongst others. The system consists of two key areas: (1) A sensor front end system designed for concurrent amperometry and potentiometry; Here we present an improved design for the front end system based on DAPPER -a low power dual amperometric and potentiometric system [13]. (2) A power and data management system for obtaining power from an external transmitter, along with data transmission.…”

“…A front-end sensor is designed for concurrent sensing with a shared reference electrode. This front-end sensor utilises four electrodes -an ion-sensitive (ISE), counter (CE), working (WE), and reference (RE) electrodes[13]. It transduces a varying frequency from the sensed current and voltage values.…”

A 92-dB-DR 126-μν Sensitivity Potentiometrie Sensor Interface with High Interference Robustness

“…Several implementations of potentiometric PoC diagnostics that make use of WPT for power supply were recently presented. The implementations in [4]- [6] do not require an external energy storage device; however, the unidirectional wireless communication path and the absence of an on-chip digital controller do not allow reconfiguration of the circuits based on the sensed signal information. As a result, the input voltage dynamic range is limited, leading to implementations suitable for only a single biochemical application.…”

“…In addition, the used interface topologies are not optimized for WPT in terms of interference robustness. For instance, single-ended front-end topologies are used in [4], [7]. A symmetrical input topology is used in [5]; however, the sensor signal is referred to ground after the input amplifier, which leads to a susceptibility to supply noise.…”