Communication circuit and approach with modulation

摘要

Various aspects of the present disclosure involve communications, and more specifically wireless communications with modulation. As may be implemented in accordance with one or more embodiments, a rectifier having a plurality of active circuits operates in first and second modes to modulate signals communicated via an antenna as follows. The first mode is at least a half-active mode in which at least one of the active circuits passes the signal, and the second mode consumes less power than the first mode. A modulator modulates a waveform of the signal by selectively operating at least one of the plurality of active circuits, therein setting an impedance of the rectifier and modulating an amplitude of the signal.

主权项

1. An apparatus comprising:
an antenna circuit configured and arranged to provide a signal having a waveform; a rectifier circuit having at least four transistors coupled together and configured to form an active full-bridge rectifier having nodes coupled to the antenna circuit, each of the at least four transistors having a control electrode; and a modulator circuit coupled to the control electrodes of the at least four transistors of the active full-bridge rectifier, the modulator circuit configured and arranged to control an active switching function for the at least four transistors, wherein one or more of the at least four transistors is disabled for a number of cycles of the signal during the active switching function, wherein the number of cycles is greater than one and is for setting an impedance of the rectifier circuit and modulating an amplitude of the signal.