Programmable Low-Power Low-Noise Capacitance to Voltage Converter for MEMS Accelerometers.

Area of Science:

• Electrical Engineering
• Sensor Technology
• Microelectromechanical Systems (MEMS)

Background:

• Capacitive accelerometers are widely used in various sensing applications.
• Existing capacitance-to-voltage converters (CVCs) often face limitations in terms of power consumption, gain control, and bandwidth programmability.
• There is a need for efficient and versatile CVCs for low-cost, low-power capacitive sensor systems.

Purpose of the Study:

• To present a novel capacitance-to-voltage converter (CVC) for microelectromechanical systems (MEMS) capacitive accelerometers.
• To achieve high transimpedance gain control and a wide programmable bandwidth.
• To design a low-cost, low-power CVC suitable for integrated sensor applications.

Main Methods:

• The CVC was designed based on a fully-differential transimpedance amplifier (TIA).
• The circuit was implemented using a standard 0.18-μm CMOS technology.
• Key performance metrics, including transimpedance gain, bandwidth, power consumption, and input-referred noise, were evaluated.

Main Results:

• The developed TIA-based CVC features 34-dB transimpedance gain control.
• It offers a programmable bandwidth spanning over a decade, from 75 kHz to 1.2 MHz.
• The CVC demonstrates a low power consumption of only 54 μW.
• At maximum gain, the equivalent input noise is 42 fA/√Hz at 50 kHz, translating to 100 μg/√Hz.

Conclusions:

• The presented CVC effectively addresses the need for versatile and efficient signal conditioning in MEMS capacitive accelerometers.
• The design's low power consumption and programmable features make it suitable for cost-sensitive and battery-operated sensor systems.
• This work contributes to the advancement of integrated MEMS sensor technology by providing a high-performance CVC.