Driver circuit for a camera voice coil motor
AssigneeApple Inc.
InventorRichard H. Tsai
Life of this patent
Estimating the term…
Abstract
A driver circuit for a camera voice coil motor (VCM) is described. A first power switch selectively conducts current from a VCM node to a power supply node, and a second power switch selectively conducts current from the VCM node to a power return node. A pulse width modulation circuit controls the first and second power switches. In another embodiment, a switch mode current control circuit sources VCM current alternately from the power supply node and the power n node, into the VCM node. Other embodiments are also described and claimed.
Claims18
A camera module comprising:
- a camera lens;
- a voice coil motor, VCM, coupled to move the camera lens and having first and second terminals, the second terminal coupled to a power return node without any intervening active devices;
- and
- a driver circuit having a switch mode current control circuit to source VCM coil current into the first terminal of the VCM alternately from a power supply node and the power return node.
A driver circuit for a camera voice coil motor, VCM, comprising:
- a power supply node;
- a power return node;
- a camera VCM node to be coupled to a coil of the VCM to conduct VCM coil current to the power return node without an intervening active device;
- a first power switch to selectively source the VCM coil current from the power supply node to the VCM node;
- a second power switch to selectively source the VCM coil current from the power return node to the VCM node;
- and
- a pulse width modulation, PWM, circuit coupled to control the first and second power switches.
An electronic device comprising:
- a camera lens;
- a camera lens actuator having a voice coil motor, VCM, coupled to the camera lens, the VCM having a first coil terminal, and a second coil terminal that is coupled to a power return node without any intervening active devices;
- a driver circuit having a switch mode current control circuit to source VCM coil current into the first coil terminal, alternately from a power supply node and from the power return node;
- an image sensor positioned to receive an optical image of a scene formed by the camera lens;
- an image processor coupled to the sensor to produce a digital image of the scene;
- and
- an autofocus processor coupled to analyze the digital image and on that basis control the driver circuit.
Dependencies are inferred from the claim text.