Power Management in Mobile Devices

The number of personal portable devices sold each year is increasing rapidly. Cell phones are ubiquitous. Worldwide sales for 2007 are shown in Figure 1.1 [1] . The mobile phone industry is currently the largest consumer electronics (CE) segment in the world. The cell phone has replaced the personal computer as the most universal piece of technology in our lives. Industry analysts indicate that cellular phones are outpacing personal computers at the rate of 5 to 1.
Personal mobile devices are increasingly becoming more than just devices for voice communication as they have a multitude of features including connectivity, enterprise, and multimedia capabilities.
Another growing application area for personal portable devices is entertainment. Devices like portable media players (PMP), FM radios, MP3 players, and portable gaming devices are found in every electronics store. Portable music has improved significantly since the days of the cassette tape; a collection with 500 h of music now fit inside a shirt pocket.
In addition, gaming devices provide portable entertainment. Portable gaming devices were pioneered by Nintendo with the Gameboy. The gaming devices evolved from simple toys into powerful computers with the progress of technology. These gaming devices turn kids into young consumers that think digitally and prepare them for the mobile device market. Figure 1.2 shows the Sony Play Station Portable which is capable of playing games, music, video, and has a Wi-Fi connection.
Information access, manipulation, and processing...