CoE 197U Power and Energy
In this lecture, we will cover the following topics:
- Power and Energy
- Energy Efficient Techniques
- Metrics
Use the provided slide deck to guide you through this discussion. The main reference for this lecture is Chapter 5 of the Digital IC book[1] and Chapter 4 of the Enabling the IoT book[2].
Power
Power consumption can be classified into dynamic power and static power. Majority of the power consumption comes from the switching of signals, or what we call dynamic power. Static power comes from leakage currents, or the current through the devices when they are supposed to be OFF. Dynamic power comes from the switching of signals, or the charging and discharging of capacitive loads. It can be computed as CLVDD2f, where CL is the capacitive load being charged/discharged, VDD is the supply voltage and f is the frequency of transition. Considering that majority of the power comes from dynamic power, and based on the above equation, we can then say that reducing the supply voltage would be the best choice to reduce power (due to the square relation of power and supply voltage). Other possible ways to reduce power is by reducing switching activity (effectively f) and/or reduce capacitance (CL).
