APPARATUS AND METHOD FOR DRIVING A VOICE COIL MOTOR OF A CAMERA LENS

摘要

The present invention relates to a device and method for driving an under damped voice coil motor (VCM) actuator of a camera lens. In one embodiment, the device for driving an under damped VCM actuator comprises a first generator operable to read a first manufacture data from an image signal processor (ISP) and to generate a half natural period, ½ Td, of the VCM actuator by selecting a value approximate to the first data in a first table of the device, a second generator operable to read a second manufacture data from the ISP and to generate the maximum overshoot, K, of the VCM actuator by selecting a value approximate to the second data in a second table of the device, an input shaping signal generator operable to read an input signal corresponding to a desired camera lens moving distance from the ISP and to generate a shaping signal according to the value of the half natural period and the maximum overshoot. The input shaping signal may be produced from second order, third order and fourth order input shaping function. The present invention also provides a simple implementation of a driver configuration to achieve a fast camera lens focus speed, yet robust to tolerate actual system deviation from a manufacture design.

主权项

1. A device for driving an under damped VCM actuator of a camera lens, comprising:
a first generator operable to read a first manufacture data from an image signal processor (ISP) and to generate a half natural period, ½ Td, of the VCM actuator by selecting a value approximate to the first data in a first table of the device, a second generator operable to read a second manufacture data from the ISP and to generate the maximum overshoot, K, of the VCM actuator by selecting a value approximate to the second data in a second table of the device, an input shaping signal generator operable to read an input signal corresponding to a desired camera lens moving distance from the ISP and to generate a shaping signal according to the value of the half natural period and the maximum overshoot value; wherein the shaping signal is a function selected from the group consisting of1)[Aiti]=[1(1+K)K(1+K)0Td2]2)[Aiti]=[1(1+K)22K(1+K)2K2(1+K)20Td2Td],and3)[Aiti]=[1(1+K)33K(1+K)33K2(1+K)3K3(1+K)30πωd2πωd3πωd]wherein Ai is the amplitude component and ti is the time component of the shaping function, Td is the nature period and K≠1;
the driving device further comprising a digital to analog converter and a buffer amplifier, wherein the digital to analog converter and buffer amplifier convert the shaping signal to the current required for a VCM actuator to drive the camera lens to a desired distance.