Power Management in Mobile Devices


  • Findlay Shearer, Senior Product Manager, Freescale Semiconductor, Texas, USA

Sealed Lead Acid…Nickel Cadmium…Lithium Ion…How do you balance battery life with performance and cost?This book shows you how!Now that "mobile" has become the standard, the consumer not only expects mobility but demands power longevity in wireless devices. As more and more features, computing power, and memory are packed into mobile devices such as iPods, cell phones, and cameras, there is a large and growing gap between what devices can do and the amount of energy engineers can deliver. In fact, the main limiting factor in many portable designs is not hardware or software, but instead how much power can be delivered to the device. This book describes various design approaches to reduce the amount of power a circuit consumes and techniques to effectively manage the available power.Power Management Advice On:•Low Power Packaging Techniques•Power and Clock Gating•Energy Efficient Compilers•Various Display Technologies•Linear vs. Switched Regulators•Software Techniques and Intelligent Algorithms
View full description


RF/wireless engineers and designers, Engineers designing mobile devices such as PDAs and games; Engineering managers, Graduate students


Book information

  • Published: December 2007
  • Imprint: NEWNES
  • ISBN: 978-0-7506-7958-9

Table of Contents

1. Introduction to Power Management in Portable Personal Devices1.1. Power Trends1.2. Mobile Devices and Applications1.2.1. Cellular Phones1.2.2. Portable Media Players1.2.3. Portable Digital Audio Players1.2.4. Portable Navigation Devices1.3. Cellular Handsets – Deeper Dive1.3.1. Cellular System Overview1.3.2. Evolution of Cellular Systems1.3.3. Cellular Handset Teardown1.3.4. Seamless Mobility - Connectivity1.4. Summary2. Chapter 2 – Hierarchical View of Energy Conservation2.1. Issues and Challenges2.1.1. Closing the Technology Gaps 2.1.2. Always On, Always Connected – Paradox of the Portable Age2.1.3. Balancing Battery Life with Performance and Cost2.2. Power versus Energy Types2.2.1. The Elements Power Consumption2.2.2. Elements of Dynamic and Static Power2.3. Hierarchy of Energy Conservation Techniques2.4. Low Power Process and Transistor Technology2.4.1. Process Technology Scaling2.4.2. Transistors and Interconnects2.5. Low Power Packaging Techniques2.5.1. Introduction2.5.2. Systems-in-Package (SiP2.5.3. Package-on-Package2.5.4. SiP versus PoP2.6. Summary3. Low Power Design Techniques, Design Methodology and Tools3.1.1. Dynamic Process Temperature Compensation3.1.2. Static Process Compensation3.1.3. Power Gating3.1.4. State Retention Power Gating 3.2. Low Power Architectural and Subsystem Techniques3.2.1. Clock Gating3.2.2. Asynchronous Techniques - GALS3.2.3. Power Saving Modes3.3. Low Power SoC Design Methodology, Tools and Standards 3.3.1. Introduction3.3.2. Low Power Design Process3.3.3. Key EDA Vendors Approach to Low Power Design3.3.4. Low Power Format Standards 3.4. Summary4. Energy Optimized Software4.1. Mobile Software Platform4.1.1. Modem Software4.1.2. Application Software4.1.3. Operating Systems for Mobile Devices4.1.4. Why an Operating System? Application Execution Environment4.2. Energy Efficient Software4.2.1. Dynamic Power Management 4.2.2. Energy Efficient Compilers4.2.3. Application Driven Power Management4.2.4. Advanced Power Management (APM)4.2.5. Advanced Configuration and Power Interface4.2.6. The Demand for Application-Driven Power Management4.3. Summary5. Batteries and Displays for Mobile Devices5.1. Introduction5.1.1. Battery Challenge5.1.2. Evolution of Battery Technology5.2. Battery Fundamentals5.3. Battery Technologies5.3.1. Sealed Lead Acid (SLA)5.3.2. Nickel Cadmium (Ni-Cad)5.3.3. Nickel Metal Hydride (Ni-MH)5.3.4. Lithium Ion (Li-Ion)5.3.5. Lithium-ion Polymer (Li-Poly)5.3.6. Other Lithium Ion Types5.4. Battery Chemistry Selection5.5. Portable Device Display Technologies5.5.1. Mobile Device Power Distribution5.5.2. Backlights5.5.3. Display Technologies 5.6. Low Power LCD Display Techniques5.6.1. Dynamic Luminance Scaling5.6.2. Extended DLS (EDLS)5.6.3. Backlight Autoregulation5.6.4. Frame buffer compression5.6.5. Dynamic Color Depth 5.7. Summary5.7.1. Batteries5.7.2. Displays6. Power Management Integrated Circuits6.1. Introduction6.2. Voltage Regulators6.2.1. Introduction6.2.2. Linear Regulators6.2.3. Switching Regulators6.2.4. Linear vs Switched6.3. Battery Management - Fuel Gauages, Charging, Authentication6.3.1. Fuel Gauges6.3.2. Battery Charge Management6.3.3. Li-Ion battery safety6.3.4. Battery Authentication6.3.5. Example of a Battery Management Unit (BMU) and Battery Protection6.4. Power Management Integrated Circuits plus ?6.5. Summary7. System Level Approach to Energy Conservation7.1. Introduction7.2. Low Power System Framework7.2.1. Advanced Energy-Management Solution7.2.2. Software for Self Optimizing Systems7.3. Low Power System/Software Techniques7.3.1. Dynamic Frequency Scaling7.3.2. Dynamic Voltage Scaling (DVS)7.3.3. Dynamic Process and Temperature Compensation (DPTC)7.3.4. Handling Idle Modes7.4. Software Techniques and Intelligent Algorithms7.4.1. Operating System7.4.2. Typical DVFS Algorithm7.4.3. Scope within Wireless Applications7.5. Freescale’s XEC - Technology-Specific Intelligent Algorithms7.5.1. XEC Framework7.6. ARM’s Intelligent Energy Manager (IEM)7.7. National Semiconductors: PowerWise™ Technology7.8. Energy Conservation Partnership7.9. Texas Instruments: SmartReflex7.9.1. Silicon IP7.9.2. System-on-a-chip7.9.3. System software7.10. Intel SpeedStep7.11. Transmeta LongRun and LongRun27.12. Mobile Industry Processor Interface – System Power Management (SPM)7.13. Summary8. Future Trends in Power Management 8.1. Converged Mobile Devices8.2. Future Processes8.2.1. Nanotechnology and Nanoelectronics8.2.2. Quantum Computing8.2.3. Micro Electrical and Mechanical Systems (MEMS)8.2.4. Biological (DNA)8.3. Future Packaging for Mobile Devices8.3.1. System Packaging Evolution8.3.2. Redistributed Chip Packaging8.3.3. System-on-Package8.4. Future Sources of Energy for Mobile Devices8.4.1. Fuel Cells8.5. Future Displays for Mobile Devices8.5.1. Electronic Paper Displays8.6. Summary8.6.1. References