Power efficient circuit design

"Do you have a Ipod or a cell phone?" If I ask this question to you, Undoubtablly, I would expect the answer will be "Yes" because portable gears already become so popular that it almost can\´t be separated from our daily life. Again, if I ask you "do you like carry the battery charger during your travel?" definitely, the answer will be "No"...I think. So this brings my topic-How to do Power Efficient Circuit Design to make customers happier with portable devices. In this paper, how to reduce power consumption in analog design is discussed. An Analog CPU concept is introduced. To reduce power consumption in analog design, integrated power management, switching output driver and dynamic circuit operation are considered to be the most effective approach to be analyzed. In circuit design level, widely using weak inversion operation, continuous time architecture and transient current reduction are listed as considerable solutions to improve power efficiency in analog circuit design for portable applications.