Project Analog - February 2009 - (Page 8)

liNEar rEgulaTor Efficiency Noise output current step-up voltage step-Down voltage solution size Low Low Low to Medium No Yes Small sWiTchiNg rEgulaTor High High Low to High Yes Yes Large chargE PumP Medium Medium Low Yes Yes Medium also require an external capacitor in order to minimize the voltage ripple applied to the load. This external capacitor needs to be much larger then the internally switched capacitor and can take up valuable circuit board space. summary All three of the dc/dc converters discussed above have advantages and disadvantages associated with them, as (Table 1) shows. Selecting the proper topology depends upon the application and what parameters are most critical. If extending battery life is a priority, then a highly-efficient switching regulator may be the best solution. If noise is a big concern, then a linear regulator is an attractive solution. Regardless of the application, focusing on the power-management circuitry is critical in achieving the desired system performance. microchiP resources Battery Power Applications Design Guide http://ww1. microchip.com/downloads/en/ DeviceDoc/39610C.pdf AN968: Simple Sychronous Buck Regulator – MCP1612 http://ww1.microchip.com/downloads/en/ AppNotes/00968a.pdf AN765: Using Microchip’s Micropower LDOs http://ww1. microchip.com/downloads/en/ AppNotes/00765b.pdf AN980: Designing a BoostSwitching Regulator with the MCP1650 http://ww1. microchip.com/downloads/en/ AppNotes/00980a.pdf MCP1703 Product Page http://www.microchip.com/ wwwproducts/Devices. aspx?dDocName=en53083 Contents Viewpoint Selecting the Right dc/dc Converter Selecting the Right Battery System Understanding the Buck Switchmode Power Converter Analog news TaBlE 1 Dc/Dc coNvErTEr ToPology comParisoN charge PumPs A charge pump utilizes a capacitor as an energy storage device. Switches connect the plates of the capacitor to the input voltage in such a way as to double, triple, invert, halve or even create an arbitrary regulated output voltage, depending uon the circuit topology. Because charge pumps charge and discharge capacitors to transfer energy, the amount of output current that this type of converter can provide is relatively low compared to the other converters mentioned, typically no more then a couple hundred mA. In terms of efficiency, noise and solution size, charge pumps fall somewhere in between linear regulators and switching regulators. The efficiency of charge pumps is better than LDOs, although switching regulators can achieve even higher efficiencies. The switches inside of a charge pump create the same type of switching noise as a switching regulator, but do not require an external inductor which radiates that switching noise. Charge pumps Microchip analog page Sample center microchipDIRECT Reference designs/ app notes Technical training 8 · PRojeCt ANAlog · VolUme 3 / NUmBeR 1 http://ww1.microchip.com/downloads/en/DeviceDoc/39610C.pdf http://ww1.microchip.com/downloads/en/DeviceDoc/39610C.pdf http://ww1.microchip.com/downloads/en/DeviceDoc/39610C.pdf http://ww1.microchip.com/downloads/en/AppNotes/00968a.pdf http://ww1.microchip.com/downloads/en/AppNotes/00968a.pdf http://ww1.microchip.com/downloads/en/AppNotes/00968a.pdf http://ww1.microchip.com/downloads/en/AppNotes/00765b.pdf http://ww1.microchip.com/downloads/en/AppNotes/00765b.pdf http://ww1.microchip.com/downloads/en/AppNotes/00765b.pdf http://www.microchip.com http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=79&redirects=analog http://ww1.microchip.com/downloads/en/AppNotes/00980a.pdf http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=79&redirects=analog http://ww1.microchip.com/downloads/en/AppNotes/00980a.pdf http://ww1.microchip.com/downloads/en/AppNotes/00980a.pdf http://sample.microchip.com/Default.aspx?testCookies=true http://www.microchipdirect.com/catalogselection.aspx?returnURL=default.aspx http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en53083 http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en53083 http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en53083 http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1423 Table of Contents for the Digital Edition of Project Analog - February 2009Project Analog - February 2009ContentsViewpointAbout Project Analog SponsorSelecting the Right dc/dc Converter for Portable ApplicationsSelecting the Right Battery System for Portable ApplicationsUnderstanding the Buck Switchmode Power ConverterComparing A/D Power Management TechniquesThermal Management of dc/dc Power ModulesAnalog NewsContact MicrochipLinkedInTreelinkMicrochip Advanced Parts Selector (MAPS)Project Analog - February 2009Project Analog - February 2009 - Project Analog - February 2009 (Page Cover1)Project Analog - February 2009 - Contents (Page 2)Project Analog - February 2009 - Viewpoint (Page 3)Project Analog - February 2009 - About Project Analog Sponsor (Page 4)Project Analog - February 2009 - Selecting the Right dc/dc Converter for Portable Applications (Page 5)Project Analog - February 2009 - Selecting the Right dc/dc Converter for Portable Applications (Page 6)Project Analog - February 2009 - Selecting the Right dc/dc Converter for Portable Applications (Page 7)Project Analog - February 2009 - Selecting the Right dc/dc Converter for Portable Applications (Page 8)Project Analog - February 2009 - Selecting the Right Battery System for Portable Applications (Page 9)Project Analog - February 2009 - Selecting the Right Battery System for Portable Applications (Page 10)Project Analog - February 2009 - Selecting the Right Battery System for Portable Applications (Page 11)Project Analog - February 2009 - Understanding the Buck Switchmode Power Converter (Page 12)Project Analog - February 2009 - Understanding the Buck Switchmode Power Converter (Page 13)Project Analog - February 2009 - Comparing A/D Power Management Techniques (Page 14)Project Analog - February 2009 - Comparing A/D Power Management Techniques (Page 15)Project Analog - February 2009 - Comparing A/D Power Management Techniques (Page 16)Project Analog - February 2009 - Comparing A/D Power Management Techniques (Page 17)Project Analog - February 2009 - Thermal Management of dc/dc Power Modules (Page 18)Project Analog - February 2009 - Thermal Management of dc/dc Power Modules (Page 19)Project Analog - February 2009 - Thermal Management of dc/dc Power Modules (Page 20)Project Analog - February 2009 - Analog News (Page 21)Project Analog - February 2009 - Contact Microchip (Page 22)Project Analog - February 2009 - LinkedIn (Page 23)Project Analog - February 2009 - Treelink (Page 24)Project Analog - February 2009 - Microchip Advanced Parts Selector (MAPS) (Page 25)Project Analog - February 2009 - Microchip Advanced Parts Selector (MAPS) (Page Cover4)http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200902http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200810http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200808http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200804http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200803http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200802http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200801http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200712http://www.nxtbook.com/nxtbooks/hearst/projectanalog_200711http://www.nxtbookMEDIA.com

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