There is an ever-growing number of embedded systems applications where energy saving and efficiency are at the top of developers’ priorities. These constraints can be due to government regulations (e.g. metering applications), a requirement to increase battery life, or simply a need to lower the electricity bill. In battery-operated systems energy efficiency often plays the most important role. In cases where developers are satisfied with their system’s battery life, increasing the energy efficiency means they can switch to a smaller and cheaper battery which will lower the overall cost. There are also situations where the operating life must be extended to the absolute maximum. For example where the battery cannot be replaced or replacement involves very high costs.