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:
Jun. 25, 2002
Filed:
Jul. 21, 2000
Michael J. Callahan, Jr., Austin, TX (US);
STMicroelectronics, Inc., Carrollton, TX (US);
Abstract
A method and circuit are disclosed for controlling the current level of a differential logic circuit having a current source, input transistors which perform current steering based upon the input to the differential logic circuit, and load transistors. The circuit includes a first transistor that forms a current mirror with the current source, a second transistor coupled to the load transistors so that the operating characteristics of the load transistors substantially match the operating characteristics of the second transistor, and current source circuitry coupled between the first and second transistors. The current level selected in the current source circuitry sets the current level in the differential logic circuit and the resistance of the load transistors so that the output voltage swing of the differential logic circuit stays within an acceptable range of voltages, regardless of the selected current level.