Sensitivity enhancement of MEMS inertial sensors using negative springs and active control

• Published in: Sensors and actuators. A, Physical Vol. 97; pp. 153 - 160
• Main Authors: Handtmann, Martin, Aigner, Robert, Meckes, Andreas, Wachutka, Gerhard K.M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01-04-2002; Elsevier Science
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Force-feedback loop; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Negative spring; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Σ/ Δ-Architecture; Negative spring; Σ/ Δ-Architecture; Force-feedback loop; Sigma-delta modulation; Microelectronic fabrication; Sensitivity analysis; Force feedback; Complementary MOS technology; Theoretical study; Inertial systems; Sensors; Experimental study; Springs; Microelectromechanical device
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/S0924-4247(01)00818-4

In this paper, we present a device in which the inherent control scheme of force-feedback loops in
Σ/
Δ-architecture
[1] is used for increasing the mechanical sensitivity of differential capacitive inertial transducers in combination with “negative springs”. As a consequence, the input-referred electronic noise and quantization-noise is significantly reduced in the signal band. Since electronic noise can influence the stability of the feedback loop,
Σ/
Δ-theory is tailored to micromechanical sense loops. This forms the basis for analyzing on the system performance and the system limitations. Results from system simulation and measurement of an accelerometer demonstrate a significant improvement in sensitivity.