What is energy-proportional sensing?
Sensing (S) is essentially a process of measurement of a physical quantity and presenting its value in a form that can be used for electronic or human data manipulation. It is a (sequential) composition of transduction (T) and conversion (C), i.e. S = T;C.
Suppose we have a way of transduction of a sensed quantity, i.e. turning it into an electrical parameter, such as voltage or current. One way of transduction could be to turn the sensed parameter into energy. The energy can then be turned into a computation whose final results could represent the energy used in this computation, which in its turn could represent the original parameter. To make such a sensor we need two aspects of proportionality (ideally, in linear relationship). One is that the original parameter is turned into the amount of energy in a proportional way, and the other is that the obtained amount of energy is turned into an information representation also in a proportional way.
Our proposed voltage sensor (see my previous posting about our patent application on voltage sensor) is based exactly on this principle. The input voltage is converted into a electric charge (energy) in a sampled capacitor, and then this charge (energy) is converted into a binary code produced by the electronic circuit which is fed by the energy of the charge.