A highly accurate piezoelectric actuator driver IC for auto-focus in camera module of mobile phone

The piezoelectric actuator is one of suitable approach for implementing Auto-Focus (AF) function in camera modules for mobile phone. In this paper, the piezoelectric actuator driver IC for AF in camera modules is designed. In the driver IC, three techniques are used for highly accurate lens position, which are self position control algorithm, Time Division Driving (TDD) scheme and frequency sweep control. With accurate lens position techniques, the lens position can be controlled within 3μm. The die area of designed driver IC is 2.0 × 1.6mm² and power consumption is 2.8mW.