Hall-effect based linear motor controller
First Claim
Patent Images
1. A method of focusing a lens in a camera module having a voice coil actuator to effect displacement of the lens, comprising:
- determining a displacement range value for the lens;
determining a per-frame value based on the displacement range value for the lens and a desired number of frames;
using the per-frame value and a current frame number to determine a value corresponding to a desired displacement of the lens; and
providing a request comprising the value corresponding to the desired displacement of the lens as an input to a device that adjusts a drive current supplied to a coil of the voice coil actuator according to the value corresponding to the desired displacement of the lens and an internal feedback loop in the device until the desired displacement of the lens has been effected by the voice coil actuator.
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Abstract
A linear motion control device for use in a linear control system is presented. The linear motion control device includes a coil driver to drive a coil that, when driven, effects a linear movement by a motion device having a magnet. The linear motion control device also includes a magnetic field sensor to detect a magnetic field associated with the linear movement and an interface to connect an output of the magnetic field sensor and an input of the coil driver to an external controller. The interface includes a feedback loop to relate the magnetic field sensor output signal to the coil driver input.
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Citations
7 Claims
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1. A method of focusing a lens in a camera module having a voice coil actuator to effect displacement of the lens, comprising:
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determining a displacement range value for the lens; determining a per-frame value based on the displacement range value for the lens and a desired number of frames; using the per-frame value and a current frame number to determine a value corresponding to a desired displacement of the lens; and providing a request comprising the value corresponding to the desired displacement of the lens as an input to a device that adjusts a drive current supplied to a coil of the voice coil actuator according to the value corresponding to the desired displacement of the lens and an internal feedback loop in the device until the desired displacement of the lens has been effected by the voice coil actuator. - View Dependent Claims (2, 3, 4, 5)
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6. A method of focusing a lens in a camera module having a voice coil actuator to effect displacement of the lens, comprising:
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determining a displacement range value for the lens by obtaining a value corresponding to a position of the lens when no current is supplied to a coil of the voice coil actuator, Obtaining a second value corresponding to a second position of the lens when a maximum drive current is supplied to the coil, wherein obtaining the second value comprises providing a maximum current drive request to a device that causes the maximum drive current to be supplied to the coil, and determining a difference between the first value and the second value; determining a value corresponding to a desired displacement of the lens based on the displacement range value; providing a request comprising the value corresponding to a desired displacement of the lens based on the displacement range value to the device, causing the device to adjust a drive current supplied to the coil according to the value and an internal feedback loop in the device until the desired displacement of the lens has been effected by the voice coil actuator.
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7. A method of focusing a lens in a camera module, comprising:
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determining a displacement range for the lens; using the displacement range to request a desired displacement of the lens; and providing the request to a device that causes displacement of the lens by a voice coil actuator, by using an internal control loop comprising a magnetic field sensor to adjust a drive current supplied to a coil of the voice coil actuator.
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Specification