Về mặt lý thuyết nó sẽ có thể để bắt đầu chuyển giao dữ liệu người dùng giữa hai thiết bị ngay sau khi thành lập một ACL và kết nối L2CAP. Bluetooth, tuy nhiên, có thể được sử dụng cho nhiều ứng dụng khác nhau, và nhiều thiết bị do đó cung cấp một số dịch vụ khác nhau với các thiết bị từ xa cùng một lúc. | 20 Chapter 2 Power Management Technologies Discrete Power Technology Processing and Packaging Microprocessors for PCs are at the forefront of the computing industry leading with huge nano-scale chips built in multi billion dollar fabrication plants. So far the success of the semiconductor industry has been assured by Moore s law a concept that underscores the fast-paced dynamic of the industry. However new chips in smaller footprints are upping the trend for increasing power densities to amazing levels. At every new technology juncture the CPU becomes denser and hotter. Keeping pace with changing densities compounded with the need for disposing the resulting heat is creating more challenges for applications designers. Providing power from the AC line is also becoming an issue for designers. The number and growth rate of electronic appliances is driving a huge demand for power prompting concerns for power distribution and energy conservation and spurring a slew of protocols and initiatives aimed at minimizing the waste of power. These requirements are pushing technology advancements beyond the traditional cost-oriented model of minimizing the appliance s Bill of Materials BOM to look for new solutions. At the core of all power management solutions from the wall to the board are power transistors. The evolution of discrete semiconductors is essential for supporting Moore s law and thereby maintaining the industry s healthy growth. Not surprisingly designing and mass producing costeffective discrete transistors capable of efficiently handling power requires increasingly sophisticated semiconductor processes and packaging. From Wall to Board Electric power is transferred to the CPU in two crucial steps from the high voltage AC line to an intermediate DC voltage and from there to the low voltage regulator VR which is needed to power the CPU. The high voltage planar technology transistor underlying this AC-DC conversion must sustain voltages in the 600-700 V range .
