| CPC H02J 50/27 (2016.02) [H02J 50/001 (2020.01); H04B 5/0037 (2013.01)] | 20 Claims |
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1. A circuit, comprising:
a first radiofrequency-to-direct current (RF-to-DC) circuit configured to receive a first signal from at least one radiofrequency sensing antenna at a first node and produce a first converted signal at a second node;
an energy storage circuit coupled to the first RF-to-DC circuit and supplied with the first converted signal;
a second RF-to-DC circuit, wherein the second RF-to-DC circuit is a replica of the first RF-to-DC circuit scaled down by a scaling factor, configured to receive said first signal at an input node and produce a second converted signal at a sensing node that is indicative of an open-circuit voltage at the second node of the first RF-to-DC circuit;
driver circuitry comprising a voltage reference generator configured to provide a voltage reference signal and coupled to said first and second RF-to-DC converter circuits;
wherein said first RF-to-DC circuit comprises an integer number N of sub-stages, at least one sub-set of sub-stages in said number N being selectively deactivatable/activatable;
wherein the driver circuitry is configured to:
i) perform a comparison between said second converted signal and said voltage reference signal, wherein said comparison produces a first signal and a second signal, the first signal having a first value when said second converted signal is higher than said voltage reference signal and the second signal having a first value when said second converted signal is lower said voltage reference signal in order to check whether the second converted signal is within a range of values proportional to said voltage reference signal; and
ii) selectively deactivate a sub-set of sub-stages in said number N of said first RF-to-DC circuit when said performed comparison has a first result, or selectively activate said sub-set of integer sub-stages in said number N of said first RF-to-DC circuit when said performed comparison has a second result.
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