A low-noise HV interface circuit for MEMS vibratory gyroscope
The paper presents a low-noise high voltage (HV) CMOS Interface ASIC designed for MEMS vibratory gyroscopes. A closed-loop control is realized in the driving mode. An in-chip level shifter is designed in the loop to achieve a high DC voltage level of 5V which can excite the gyroscope. A DC biasing method is adopted in the interface circuit to convert the amplitude-modulated capacitive signal into voltage. The chip occupies 2.5 × 2.0mm2 in a 0.35 µm 2P3M BCD HV process, which offers buried layer and high voltage N-well isolation to block out the potential coupling noise. Simulation results show that the drive axis can accomplish a closed-loop self-oscillation of the MEMS gyroscope.