The patent's assignee for patent number 8773122 is
News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to a hall element control circuit for supplying a constant-current bias current to a hall element.
"Hall elements are elements used to detect the position of an object. For example, the hall elements are used to detect the lens position in an autofocus control of a camera. Generally, the hall elements are driven by a constant current in order to eliminate adverse effects caused by variations in the elements and a change in the environments.
"Many of mobile phones and smart phones available today are provided with built-in cameras and also a camera having an auto-focusing function is in practical use today. A smaller size and a further simplified structure are required for the camera module mounted on such a mobile phone and its input-output wiring."
As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "A hall element control circuit according to one embodiment of the present invention is connected to a hall element via a wiring member and controls the hall element, and it includes: a first terminal for supplying a bias voltage to a high-potential-side input terminal of the hall element; a second terminal for supplying a ground potential to a low-potential-side input terminal of the hall element; a transistor whose source terminal is connected to a power supply potential and whose drain terminal is connected to the first terminal; and an operational amplifier for controlling a gate voltage of the transistor by differentially amplifying a voltage between a predetermined set voltage and a voltage at the first terminal.
"Another embodiment of the present invention provides a focus control circuit. The focus control circuit is a focus control circuit mounted on an image pickup apparatus including a lens, a driver element for adjusting the position of the lens, and a position detecting element for detecting the position of the lens, and this focus control circuit includes: an equalizer configured to generate a control signal used to adjust the position of the lens to a target position based on a difference between the position of the lens identified by an output signal of the hall element and the target position which is set externally; a PWM modulator configured to generate a PWM signal according to the control signal generated by the equalizer; a driver unit configured to generate a drive current used to drive the driver element according to the PWM signal generated by the PWM modulation unit; and the above-described hall element control circuit.
"Still another embodiment of the present invention provides an image pickup apparatus. The image pickup apparatus includes: a lens; image pickup devices for converting light transmitted through the lens into an electrical signal; a driver element for adjusting the position of the lens; a hall element for detecting the position of the lens; an image signal processor for determining a target position of the lens based on an output signal of the image pickup devices; and the above-described focus control circuit for driving the driver element.
"Optional combinations of the aforementioned constituting elements, and implementations of the invention in the form of methods, apparatuses, systems and so forth may also be effective as additional modes of the present invention."
For additional information on this patent, see: Kura, Takeshi; Tsuda, Hiroyuki; Kamiya, Tomonori; Nagai, Hiroki. Hall Element Control Circuit. U.S. Patent Number 8773122, filed
Keywords for this news article include: Electronics,
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