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Embedded designers need to seek innovative approaches to meeting the stringent requirements of emerging consumer products. One approach is to move away from discrete solutions to integrated system-on-a-chip (SoC). When it comes to managing the power, audio, or other needs of a mobile device, an all-in-one SoC is a definitive example of how an integrated solution can offer more benefits than the sum of its individual parts. Integrated solutions also speed time to market.

It is possible for designers to use leading-edge SoC chips that offer integrated solutions for subsystems that were previously only available with discrete designs. Two key integrated subsystems for portable devices are presented in relation to a hardware development platform for developers and manufacturers of smart phones, PDAs, GPS systems and other portable applications running Windows CE 5.0 or Windows CE 6.0 on custom embedded devices using the Monahans applications processor.

Up until now, the discrete approach to managing system functions has been more than adequate. In fact, in some ways, it was the most efficient approach to the task at hand. One example of this is in power management. Even as devices began to require more sophisticated power management, developers were able to go to market quickly using a variety of off-the-shelf components, likely using components from different vendors in the same device. Frequently, power subsystems of even highly complex circuits were made up of just a couple of power supplies and a few discrete components, such as LDOs and buck converters.

Such an approach is no longer adequate, however. Today's processors feature advanced power management capabilities. A discrete approach is inefficient to reap all of the gains possible from modern applications processors, such as the Intel Monahans platform, thus, wasting battery life and resulting in devices that are larger than they really need to be.

At a minimum, a typical handheld device requires several power domains. The main applications processor needs at least two power domains to cover a low-voltage core and high-voltage I/O pins. Additional domains are required to support the device's memory, display, memory expansion slots, and other features, such as audio functionality or sensors.

A designer could try to combine domains, using one set of discrete parts to handle the power needs for several unrelated functions of the device. This reduces system complexity, but is inefficient as the different functions have their own power needs and, therefore, may not be able to operate as efficiently as possible. Each domain would have to supply enough power for the most demanding function attached to it. Power may be wasted on functions that don't need quite as much. Also, you would lose the ability to serve those connected functions independently. They must be controlled as a group.

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