Readout Electronics with Bandpass Delta-Sigma A/D Converter for a Bulk Micromachined Capacitive Gyroscope

This paper presents a fully integrated readout electronics designed for a bulk micromochined capacitive gynoscope. The readout chain is composed of a charge sensitive amplifer, analog signal processing and a δσ-type A/D converter. The analog signal processing consists of a high-pass filter, a variable-gain amplifier, another high-pass filter and a low-pass filter. The system achieves a measured capacitance sensitivity of 4.00 aF (rms) in a 100 Hz band centered at 8.462kHz, consuming 2.9 mA. The signal frequency can vary between 8-10 kHz, depending on the gyroscope element. A full microelectromechanical angular velocity sensor system has been built using the readout electronics described together with external electronics, and its operation has been verified.