The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 06, 1999
Filed:
Jan. 08, 1997
Geoffrey E Brehmer, Lexington, TX (US);
Joe W Peterson, Austin, TX (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
An intermediate frequency gain and rectifying stage for an IF system is implemented with a high swing folded-casecode structure terminated into a current-mirror load. The signal-path outputs are derived from the current-mirror loads, and the rectification and current-limiting RSSI functions are performed with two additional constant-current sources and two additional current-mirror loads. One load current from one leg or current path of the signal-path gain-stage is mirrored into a constant-current source and a second current-mirror structure. A second leg or current path of the signal-path gain-stage is likewise mirrored into yet another constant-current source and another current-mirror structure. When the input signal is not present, the load currents in the signal-path gain-stage are equal and the rectified output signal on an output node IOUT is constant or set to zero. With a differential input signal present, the load currents in the signal-path gain-stage produce a plus delta-current and minus delta-current. The plus delta-current, which represents a difference between the current in one of the legs of the signal-path gain-stage and the current of a corresponding constant current source, is mirrored to generate the RSSI current output signal at the IOUT node. Likewise, during the negative-half input-cycle the signal-path load currents are again mirrored and only the plus delta-load-current is rectified and output on the output node IOUT.