In this embodiment, the switch mode current control circuit sources the VCM current alternately from the power supply node and the power return node, into the VCM node. Explore more advantages of iCoupler-based digital isolation products. In order to make the best use of the increased resolution, effective and rapid autofocus (AF) must accompany the increase in pixels. FIG. 5 depicts an alternative to the arrangement of FIG. 1, where in this case the VCM node 6 is directly connected to the terminal A of the VCM 3, and
The lens actuator contains a voice coil motor (VCM) to which the lens is coupled. We collaborate with our customers to accelerate the pace of innovation and create breakthrough solutions that are ahead of what’s possible.See the InnovationsSocialQuick LinksAbout ADIAlliancesAnalog DialogueCareersContact usInvestor RelationsNews RoomQuality & ReliabilitySales The communications interface 13 may contain registers that can be programmed to store a desired PWM duty cycle setting, with which the PWM circuit is programmed. alternately on and off, conduct the VCM current from the VCM node 6 to the power supply node 7. Check This Out
The final or desired duty cycle setting is then signaled to the driver circuit 2, and then a picture (which is now in focus) is taken at the corresponding lens position. The waveforms in FIG. 2 depict a fifty percent duty cycle, as an example. It is mechanically robust, shock-resistant, and has low-cost mechanics. Product Selection Table Laser Drivers Laser Drivers Hold Shift Key for secondary sortingSortOrderPart#Vsupply (typ)(V)Data Rate (max)(bps)Pulse Width Distortion(s p-p)Output Rise Time (typ)(s p-p)Modulation Current (max)(A)Ibias (max)(A)MSA ComplianceLoop Control TypeUS Price
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5838515Apr 30, 1996Nov 17, 1998Quantum CorporationPWM/linear driver for disk drive voice coil actuatorUS7466095Jun 19, 2006Dec 16, 2008Marvell International Ltd.Voice coil motor control system and method using pulse These factors are important because camera modules with autofocus are currently the highest-volume products in this market. Think you have reached this page in error? The AD5823/AD5823-1 are designed to drive both spring- preloaded and nonspring linear voice coil motors used in applications such as lens autofocus, image stabilization, and optical zoom.
Figure 5 shows a block diagram of the AD5821. Mems Lens Actuator For optimal site performance we recommend you update your browser to the latest version.Update Microsoft Internet ExplorerSearchCross Reference SearchSearch TipsParametric SearchProductsApplicationsDesign CenterCommunityEducationSupport Print My Analog ×Four Easy Search Tips1.Press the Enter The start current, or threshold current that must be exceeded for any displacement of the spring-preloaded linear motor to occur, is usually 20 mA or greater. http://www.analog.com/en/products/interface-isolation/isolation/isolated-gate-drivers.html Figure 6.
Send an email to [email protected] Figure 3. You can change your cookie settings at any time but parts of this site will not function correctly without them. It can be used for both AF and zoom applications, and no hold power is required to maintain lens position after a lens movement is complete.
Mems Lens Actuator
The driver circuit also has a switch mode current control circuit. That same terminal of the VCM 3 may also be directly connected to a dc power supply, here a battery 4. Vcm Actuator Figure 4 shows the transfer curve of a typical spring-preloaded linear motor for autofocus—and the dimensions of a typical VCM intended for use in a camera phone. Voice Coil Motor Images(6)Claims(15) What is claimed is: 1.
Figure 4. A pulse width modulation circuit controls the first and second power switches. An emerging actuator technology is based on piezoelectric materials, of which there are many flavors. The driver circuit may be implemented in a six-pin integrated circuit package and may be used for controlling the VCM of an autofocus lens actuator.
BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which The coil 5 is attached to the lens holder 19, and is located within a magnetic flux air gap of a magnet system 23. The camera module of claim 8 wherein the driver circuit and the communications interface are in the same integrated circuit package. 10. Diode D1 provides output protection, and dissipates the energy stored in the voice coil when the device is powered down.
In 2000 Samsung released the SCH-V200, a 0.3-megapixel (MP) camera phone, and in 2003 NTT DoCoMo launched the first autofocus handset camera, the 1.3-MP P505iS. When the autofocus mechanism is invoked, the desired position of the lens (as computed by the autofocus processor) is translated into a driver level or driver value. Completing the CAPTCHA shows you are a human and gives you temporary access to Octopart.
Our drivers support a variety of MSA-compatible modules such as SFP+, SFP with SFF-8472 Digital Diagnostics, SFF, 4× Fibre Channel, XFP, XENPAK, X2, and MSA-300.
As VCM actuators are reduced in size, the preloaded balance spring strength is also reduced. The power_down line may be used by the off-chip processor to asynchronously command the driver circuit 2 to enter a sleep mode in which the second power switch 16 is turned Figure 2 is a generic block diagram, or signal chain, of a digital camera. For optimal site performance we recommend you update your browser to the latest version.Update Microsoft Internet Explorer Subscribe Toggle navigation Menu Search Analog Dialogue AboutArchivesRAQs Resources Technical ArticlesTechnical BooksFAQsVideosWebcastsApplication NotesAnalog.comEngineerZoneWikiLinear.comSubscribeSign upProvide
In shutdown mode, all internal blocks are powered down. DSCs are cameras, first and foremost—while the primary function of the handset is to make a call and speak to somebody.