Circuits and methods for calibrating lens displacement

Abstract

Embodiments of the present invention include circuits and methods for calibrating lens displacement in a voltage controlled actuator. In one embodiment, a calibration circuit comprises a programmable voltage source that provides a voltage to a control terminal of an actuator to set a lens displacement, a switch that selectively decouples said programmable voltage source from said control terminal, a current source that provides a reference current to said control terminal when the control terminal is decoupled from said programmable voltage source, a comparator that senses a voltage difference between said programmable voltage source and said control terminal, and a timer coupled to an output of the comparator. The timer measures a time period required to increase the control terminal voltage. The capacitance of the actuator may be determined and used to calibrate the position of a lens.

Dependencies are inferred from the claim text.