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300-mW solar panel for portable products

 

With Sharp’s LR0GC02 solar panel you can directly power a device, recharge the battery, or extend the interval between battery charges for a range of portable and mobile products. The panel measures 4167.5 mm —which amounts to an area of 27.7 cm2—and is 0.8 mm thick; it can deliver 300 mW in full sunlight, a maximum of 60 mA at 5V. Sharp builds the panel with ten cells that it fabricates in polycrystalline silicon, for a peak efficiency of 12.8%. The panel is easy to build into the casings of portable devices; Sharp says that it also has taken account of the possibility that, acting as a power supply while being open to the external environment, the panel might pick up electromagnetic interference. Connections from the panel have built-in EMI suppression. The cells are redundantly connected so that the panel will still deliver full power even if any single internal connection should suffer damage.

Over the next year, Sharp will introduce further photovoltaic components for mobile applications, beginning with a more compact 5V panel with a 130-mW output in the fi rst quarter of 2010, before offering types with a 0.5 and 1V output voltage in output levels of 30, 60 and 300 mW.

This product line represents a departure for Sharp, whose PV (photovoltaic) solar cells you may be familiar with in the context of large-scale arrays for power generation. Production of PVs is one part of the company’s declared intention to “become an environmentally advanced company”. This objective cuts across its product lines; as well as the production of solar cells, it is working to bring to market LED lighting to replace not only incandescent and fl uorescent lamps in domestic and commercial lighting, but also high-intensity-discharge lamps for street lighting. In its LCD-panel and television business, Sharp is also working to reduce energy consumption. The company seeks to achieve this goal partly by the conversion of LCD backlighting away from coldcathode fl uorescents and to LEDs; and partly by picture processing and contrast management to reduce the level of light required of the backlight to produce a visually satisfying picture.

One of Sharp’s recent introductions for energy-saving displays is the memory-inpixel LCD. On larger displays, you can use this concept to show information that changes relatively slowly —on scale of a few times per second or slower, rather than at video speeds—with a signifi cant reduction in energy consumption in associated circuitry and in display drivers. As the name implies, each TFT (thin-fi lm-transistor) pixel also has a memory cell; you write data to it as if it were any other memory and at a power level around 1% that of a conventional LCD—the state of the pixel remains latched until you rewrite it. The LR0GC02 PV panel’s 300-mW output is, Sharp says, suffi cient to operate a memoryin- pixel LCD plus relevant driver components as a standalone unit without an additional power supply. Together, the company suggests, memoryin- pixel LCDs and the new solar panel offer the basis for a range of network-independent devices such as thermometers and sensors for home automation systems, GPSassisted bicycle computers or portable pulse-rate monitors, for example.

A longer version of this article appears at www.edn-europe.com/article.asp?articleid=3459.

Sharp, www.sharp-eu.com.