Implementation of phase-locked loop control for MEMS scanning mirror using DSP

The present study has employed the phase-locked loop control method to ensure the operating of MEMS actuators at their resonant frequency. In this study, the control algorism was simulated by the MATLAB. Further, the digital signal processing (DSP) technique was adopted to implement the concept of phase-locked loop control algorithm. Thus, a wide VCO lock-in dynamic range was achieved. In applications, the optical scanners fabricated using the SOI wafer and MOSBE process were respectively employed to demonstrate the present technique. The test show that the resonant frequency was tracked for various driving voltages, loop gains, and initial frequency offsets. Thus, the variation of the scanning angle resulted from the offset of the resonant frequency of the devices can be prevented.

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