This paper presents the implementation of an analog signal-processing ASIC to detect an angular velocity signal from a vibratory angular velocity detection sensor. The output of the sensor to be appeared as the variation of the capacitance value in th...
This paper presents the implementation of an analog signal-processing ASIC to detect an angular velocity signal from a vibratory angular velocity detection sensor. The output of the sensor to be appeared as the variation of the capacitance value in the structure of the sensor was detected using charge amplifiers and a self oscillation circuit for driving the sensor was implemented with a sinusoidal self-oscillation circuit using the resonance characteristics of the sensor. Specially an automatic gain control circuit was utilized to prevent the deterioration of self-oscillation characteristics due to the external elements such as the characteristic variation of the sensor process and the temperature variation. The angular velocity signal, amplitude-modulated in the operation characteristics of the sensor, was demodulated using a synchronous detection circuit. A switching multiplication circuit was used in the synchronous detection circuit to prevent the magnitude variation of detected signal caused by the amplitude variation of the carrier signal. The ASIC was designed and implemented using 0.5㎛ CMOS process. The chip size was 1.2mm × 1mm. In the experiment under the supply voltage of 3V, the ASIC consumed the supply current of 3.6㎃ and noise spectrum density from dc to 50Hz was in the range of -95dBrms/ SQRT {Hz}