A Microwatt Dual-Mode Electrochemical Sensing Current Readout With Current-Reducer Ramp Waveform Generation

Area of Science:

• * Integrated circuit design
• * Electrochemical sensing technology
• * Low-power electronics

Background:

• * Traditional electrochemical sensing often requires bulky passive components and suffers from noise.
• * Developing compact, low-power, and high-resolution electrochemical readout circuits is crucial for portable and advanced sensing applications.
• * Cyclic voltammetry (CV) and chronoamperometry (CA) are key electrochemical techniques requiring precise current measurement.

Purpose of the Study:

• * To develop a fully integrated electrochemical sensing chip with a sub-Hz ramp generator and a low-noise potentiostat.
• * To achieve high current resolution and linearity with minimal power consumption.
• * To demonstrate the chip's performance in dual-mode (CA/CV) measurements.

Main Methods:

• * Design and fabrication of an electrochemical sensing chip using a 0.18-μm CMOS process.
• * Integration of a current-reducer pattern generator and a current-mirror based chopper-stabilization potentiostat.
• * Incorporation of a counter-based time-to-digital converter for signal processing.

Main Results:

• * Achieved a current resolution of 41 pA within a ±5 μA range with R² linearity of 0.998.
• * Demonstrated ultra-low power consumption of 16 μW from a 1.2 V supply.
• * Obtained a sensing current dynamic range of 108 dB and power efficiency of 0.31.

Conclusions:

• * The integrated chip successfully performs dual-mode (CA/CV) electrochemical measurements with high sensitivity and low power.
• * The novel design overcomes limitations of large passive components and noise in electrochemical readout circuits.
• * This technology enables miniaturized and efficient electrochemical sensing systems.