When an electronic circuit or system is operating, it will consume power from either a fixed or portable power supply. The power consumption for some circuits can be large, so any reduction in the power consumption of the circuit is beneficial:
It will consume less power and so be cheaper to operate.
It will be suitable for portable, battery-operated systems required to operate for long durations between charges.
It will require less heat removal (some ICs such as the microprocessor will generate heat, which must be removed so the microprocessor can operate without failure), and so the heat removal system would be smaller and cheaper.
The power supply would be smaller, lighter, and cheaper.
Power consumption can be considered by looking at all stages in the creation and use of the design, in particular by considering:
Design architecture. Design circuits using circuit architectures that will consume less power.
Fabrication process. Within an IC the circuits consist of transistors, resistors, and capacitors. Most ICs are silicon based, and the circuits are bipolar and MOS transistors. CMOS is suited for low-power, low-voltage circuits, and static CMOS circuits provide low-power consumption when the circuit activity is low.
Reduced power supply voltage. Using electronic components that can operate at low power.
Minimized circuit activity, keeping signal logic transitions from 0 to 1 and 1 to 0. In static CMOS logic gates, current flows when nodes in a digital logic design change their logic levels, which happens when the transistor switches move from closed to open and open to closed positions. If this activity is reduced, then less current would be required to flow from the power supply.
Power management features. Some ICs provide the ability to shut down parts of the circuit when they are not used. (For example, RF transmitters consume considerable power when the RF circuitry is active, but this circuitry might only be required to be operational for short periods of time.) Additionally, some microprocessors allow reduced clock frequency within the microprocessor itself when the required activity of the microprocessor is low.