A high-precision readout circuit for MEMS sensors operating across a wide temperature range

Area of Science:

• Electrical Engineering
• Sensor Technology
• Microelectronics

Background:

• Accurate signal detection is vital for Micro-Hemispherical Resonator Gyroscope control systems.
• Existing amplifiers face challenges in detecting small currents and maintaining stability across temperature variations.

Purpose of the Study:

• To design and validate a fully differential transimpedance amplifier (TIA) for enhanced microsensor current detection.
• To achieve adjustable gain and stable performance over a wide temperature range.

Main Methods:

• Developed a two-stage, fully differential TIA architecture with adjustable feedback resistance.
• Integrated a high-precision bandgap reference (BGR) with nonlinear term cancellation and multisectional curvature compensation.
• Implemented the design using 180 nm Bipolar-CMOS-DMOS technology.

Main Results:

• The TIA demonstrated high gain and flexible gain adjustment capabilities through simulations.
• Experimental results confirmed a capacitance resolution below 1 aF for gyroscope front-end readout.
• The TIA operated reliably within a temperature range of -40 to 65°C.

Conclusions:

• The proposed TIA is effective for detecting small currents in microsensor applications, particularly for Micro-Hemispherical Resonator Gyroscopes.
• The integrated BGR ensures stable reference current, critical for readout circuit accuracy.
• The amplifier's performance across a wide temperature range makes it suitable for demanding environments.