Integrated Gm-C based PI controller for MEMS gyroscope drive loop

PI controller is an important element in MEMS gyroscope drive loop design, which helps the loop to maintain stability and obtain an optimal transient response. This paper presents an integrated Gm-C based PI controller for MEMS gyroscope drive loop. An analysis of the drive loop with PI controller is first given. The analysis reveals that sufficient tunable properties and low integrator loss should be pursued for the PI controller design. Then in the controller implementation, only one OTA is used to realize the PI control and subtract function, which minimizes the power consumption and chip area. A passive RC network in the controller introduces only one extra pad, while still promises sufficient tunable properties and low integrator loss. The chip is fabricated in a 0.35μm CMOS technology with 5V supply voltage. The chip consumes less than 1mW and its area is only 0.18×0.08 mm².