When talking about ultra-low power, it is not always simple to communicate the orders of magnitude at play in way which can be apprenhed easily by everyone. At EM Microelectronic we like to take the kinetic energy contained in a falling raindrop. Everyone has a sense of what it means to be hit by a falling drop of water. If there was a means to harvest this energy, this would represent an average of 1mJ or 1 mW during one second.
Stretching this amount of energy out over time, would allow for example to power a modern analogical quartz watch during more than 10 minutes. The consumption of a modern quartz watch is a bit less than 1µA @ 1.55V (1.55µW). Now, roughly 90% of this energy is used by the watch motor to move the hands and only 10% (actually about 140 nanoWatts) by the integrated circuit.
At EM Microelectronic, ultra-low power is at the heart of every integrated circuit design.