Patent ID: 7375578

Claim:
A radio frequency RF envelope detection circuit comprising the following: an input terminal configured to receive an Alternating Current (AC) signal during operation; an output terminal; a first current source or sink configured to provide or draw a current during operation; an AC coupling circuit coupled to the input terminal of the RF envelope detection circuit so as to superimpose a portion of the AC signal received at the input terminal onto the current provided or drawn by the first current source or sink during operation; a rectification circuit having an input terminal configured to receive or provide at least a portion of the current provided or drawn by the first current source or sink with the superimposed portion of the AC signal, the rectification circuit configured to rectify the received or provided current onto an output terminal of the rectification circuit; a voltage amplifier having an input terminal coupled to the output terminal of the rectification circuit, and having an output terminal that is coupled to the output terminal of the RF envelope detection circuit; a second current source or sink coupled to the output terminal of the RF envelope detection circuit and configured to draw or provide a current from the output terminal of the RF envelope detection circuit, the current provided or drawn by the second current source or sink being of approximately the same magnitude as the current provided or drawn by the first current source or sink, wherein if the first current source or sink acts as a current source to provided current, the second current source or sink acts a current sink to draw current, and wherein if the first current source or sink acts a current sink to draw current, the second current source or sink acts as a current source to provide current; and a capacitor coupled to the output terminal of the rectifier so as to store excess charge provided by the rectifier that is in excess of the magnitude of the current provided by the current source.