Apparatus and method for differential comparison of digital words
AssigneeSun Microsystems, Inc.
InventorWillem De Lange
Life of this patent
Estimating the term…
Abstract
A circuit for comparing a first digital word to a second digital word includes a precharge circuit to generate an initial match signal, an initial inverse match signal, and a virtual ground signal in response to an input clock signal and an inverse input clock signal. Each comparison circuit of a set of comparison circuits generates a computed match signal and a computed inverse match signal based upon a selected bit of the first digital word and a corresponding selected bit of the second digital word. A signal differential sensing circuit derives a match signal for the first digital word and the second digital word based upon the virtual ground signal, the input clock signal, the computed match signal, and the computed inverse match signal.
Claims17
A circuit for comparing a first digital word to a second digital word, comprising:
- a precharge circuit to generate an initial match signal, an initial inverse match signal, and a virtual ground signal in response to an input clock signal and an inverse input clock signal;
- a set of comparison circuits, each comparison circuit of said set of comparison circuits generating a computed match signal and a computed inverse match signal based upon a selected bit of said first digital word and a corresponding selected bit of said second digital word;
- and
- a signal differential sensing circuit to derive a match signal for said first digital word and said second digital word based upon said virtual ground signal, said input clock signal, said computed match signal, and said computed inverse match signal.
A method of comparing a first digital word to a second digital word, said method comprising the steps of:
- controlling a computed match signal on a match signal line and a computed inverse match signal on an inverse match signal line with a set of comparison circuits that compare selected bits of said first digital word to corresponding selected bits of said second digital word;
- selectively enabling a signal differential sensing circuit with a clock signal and a virtual ground signal;
- and
- deriving a match signal from said signal differential sensing circuit's processing of said computed match signal and said computed inverse match signal.
Dependencies are inferred from the claim text.