Piezoelectric motors are used in digital cameras for autofocus,zooming and optical image stabilization. Theyare relatively small, lightweight and effi cient, but theyalso require a complicated driving scheme. Traditionally,this challenge has been met with the use ofseparatecircuits, including a step-up converter and an oversizedgeneric full-bridge drive IC. The resulting high componentcount and large board space are especially problematicin the design of cameras for ever shrinking cell phones.The LT®3572 solves these problems by combining astep-up regulator and a dual full-bridge driver in a 4mm× 4mm QFN package. Figure 1 shows a typical LT3572Piezo motor drive circuit. A step-up converter is usedto generate 30V from a low voltage power source suchas a Li-Ion battery or any input power source within thepart’s wide input voltage range of 2.7V to 10V. The highoutput voltage of the step-up converter, adjustable upto 40V, is available for the drivers at the VOUT pin. Thedrivers operate in a full-bridge fashion, where the OUTAand OUTB pins are the same polarity as the PWMA andPWMB pins, respectively, and the OUTA and OUTB pinsare inverted from PWMA and PWMB, respectively. Thestep-up converter and both Piezo drivers have their ownshutdown control. Figure 2 shows a typical layout
上传时间： 2013-11-18
上传用户：hulee
This Symbian C++ code example demonstrates how to easily use the onboard camera with zoom and autofocus, utilising an accompanying CameraWrapper made by Forum Nokia. The Camera Wrapper supports all Nokia s S60 devices based on S60 3rd Edition and newer, providing a unified interface for various Symbian and S60 camera APIs some of which have previously been Feature Pack specific or only available via an SDK plug-in. The example application supports the use of both the keypad and touch UI. The application can be self-signed, but it also provides an option to use the dedicated camera key (Symbian signing required). The example application replaces the separate examples published for S60 3rd Edition, FP1 (S60 Platform: Camera Example with autofocus Support v2.2) and FP2 (S60 Camera Example autofocus 3rd Ed FP2).
标签： demonstrates Symbian example onboard
上传时间： 2013-12-11
上传用户：hopy
