Low power and highly precise closed-loop driving circuits for piezoelectric micromirrors with embedded capacitive position sensors

This work presents an integrated closed-loop driving circuit for previously reported PZT resonant micro-mirrors, which is based on embedded capacitive position sensors for minimizing the system footprint. Signals with a high SNR of 84 dB were measured, when the mechanical scan angle of the micro-mirror was 2◦, so that high controlling resolution of 14 bit for the complete motion range of the mirror is enabled. The total power consumption of the closed-loop system is only 0.86mW. Measurement results of the closed-loop driven micromirror system are presented, demonstrating its competitiveness due to the great reliability, high precision and low-power consumption. Additionally, the implementation and performance of a self-resonant loop is discussed. Finally, the fabrication, temperature dependency and performance of embedded capacitive position sensors for single and dual axis PZT resonant micro-mirrors is evaluated and presented.