Project Analog - December 2007 - (Page 14)

runtime measurements for a hybrid power source By Garry Elder Texas Instruments / Dallas, TX / www.ti.com Contents Viewpoint Charging lithium-ion batteries New trends in battery-powered portable devices Low power design: LDO thermal considerations Analog news Here’s how a hybrid battery works and why it might be right for your portable application T he demand for longer run time in portable applications is driving the emergence of fuel cells as a new power source in this end equipment space. However, there are still challenges to overcome with a “fuel-cellonly” approach in portable power applications. One solution is to make the power source a hybrid. Integrating a fuel cell with a battery, supercapacitor, or other power storage device as a combined power source solves several dynamic power supply and thermal issues. However, it generates power management issues of its own. The hybrid power source In the following architecture discussions, the hybrid system is defined 14 · Project AnAlog · dec 07 as a combination of a fuel cell and a battery. That holds true for a variety of fuel cell and battery types, or replacements such as ultracapacitors or supercapacitors. However, each complete solution is tailored to meet the unique needs of the chosen fuel cell and battery. Key system elements of the hybrid include the fuel cell, fuel cartridge, battery, system load, dc input supply, and power controller (see Figure 1). The combined fuel cell and battery is labeled as a hybrid power source (HPS). The above system, at various stages of use, can provide three energy sources and two loads. When the system is not plugged into a dc supply, a combination of the fuel Microchip analog page Battery charger overview Sample center microchipDIRECT Reference designs/ app notes Technical training http://www.ti.com http://www.microchip.com http://www.microchip.com/analog http://www.microchip.com/analog http://www.microchip.com/batterychargers http://www.microchip.com/batterychargers http://sample.microchip.com/Default.aspx?testCookies=true http://www.microchipdirect.com/catalogselection.aspx?returnURL=default.aspx http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1423

Table of Contents Feed for the Digital Edition of Project Analog - December 2007

Project Analog - December 2007 Contents Viewpoint About Project Analog Sponsor4 Charging Lithium-Ion Batteries: System Considerations New Trends In Battery-Powered Portable Devices Low Power Design: LDO Thermal Considerations Runtime Measurements for a Hybrid Power Source Battery-Powered System Design Considerations Analog News—Analog News from Multiple Sources Enter to Win an iPhone Contact Project Analog Sponsor Mindi™ Battery & Power Circuit Simulator Microchip Advanced Parts Selector (MAPS)

Project Analog - December 2007

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