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:
Feb. 22, 2000
Filed:
Jul. 16, 1997
Kirk B Ashby, Reading, PA (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A multi-stage mixer circuit has two or more mixer stages, each stage having a mixer core and successive mixer cores being separated by one or more current mirrors. By using current mirrors to process the currents generated by the mixer cores, instead of current-to-voltage and voltage-to-current converters as in the prior art, the present invention provides a mixer circuit with reduced signal distortion and power dissipation. In one embodiment, the two mixer cores of a two-stage mixer circuit are implemented using the same type of transistor devices (e.g., N-type), and there are two current mirrors between the mixer cores. In another embodiment, the two mixer cores of a two-stage mixer circuit are implemented using different types of transistor devices (i.e., one N-type and the other P-type), and there is only one current mirror between the mixer cores. A mixer circuit of the present invention may have an initial voltage-to-current converter to convert an input voltage signal into a current for the first mixer core. A mixer circuit of the present invention may also have a current-to-voltage converter to convert the current generated by the last mixer core into an output voltage signal. Alternatively, the last mixer core could be followed by a final current mirror that mirrors the current generated by the last mixer core.