(12) United States Patent ao) Patent No.: us 6,381,729 Bi
Archambeault (45) Date of Patent: Apr. 30,2002
(54) DATA PROCESSING SYSTEM AND METHOD FOR EFFICIENT DETERMINATION OF RETURN CURRENT SPREAD
(75) Inventor: Bruce Roy Archambeault, Durham, NC (US)
(73) Assignee: International Business Machines Corporation, Armonk, NY (US)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/282,300
(22) Filed: Mar. 31, 1999
(51) Int. CI.7 G06F 17/50
(52) U.S. CI 716/5; 716/4; 716/15
(58) Field of Search 716/1, 4, 5, 15;
703/2
(56) References Cited
U.S. PATENT DOCUMENTS
5,625,578 A * 4/1997 Du Cloux et al 364/578
5,812,434 A * 9/1998 Nagase et al 364/578
6,064,808 A * 5/2000 Kapur et al 395/500.23
6,163,762 A * 12/2000 Rautio 703/5
OTHER PUBLICATIONS
Oing et al., "Some Remarks ont eh Prediction ol Electromagnetic Radiation from PCBs Using the Method ol Moments," Electromagnetic Compatibility Conlerence, Sept. 1994, pp. 196-201.*
Matsui et al., "SPICE Based Analysis ol Radiation from
PCBs and Related Structures," IEEE 1997, pages 320-325.*
Kaires, "Radiated Emissions from PCB Traces Including the
Effect ol Vias, as a Function ol Source, Termination and
Board Characteristics," IEEE 1998, pp. 872-877.*
Gravelle et al, "EMI/EMC in PCBs—A Literature Review,"
IEEE Trans, on Electromagnetic Compatibility, Vol. 34, No.
2, May. 1992, pp. 109-116.*
Fujio et al., "Modeling and Analysis on Pass-through Current Decoupling Method for Multi-layer PCB," Int'l Symposium on Electromagnetic Compatibility, May 1999, pp. 365-368.*
* cited by examiner
Primary Examiner—Matthew Smith
Assistant Examiner—Leigh Marie Garbowski
(74) Attorney, Agent, or Firm—Bracewell & Patterson,
LLP; J. Bruce Schelkopl
A data processing system and method are disclosed for efficiently determining a total return current spread at an evaluation point in a relerence plane in a printed circuit board. A plurality of critical ones of a plurality of traces included within the printed circuit board are identified. For each one of the plurality of critical ones of the plurality of traces, a return current function is determined including a return current value produced by only each one of the plurality of critical ones of the plurality of traces at each point in the reference plane. A total return current spread is determined at the evaluation point utilizing the return current function associated with each one of the plurality of critical ones of the plurality of traces.
8 Claims, 5 Drawing Sheets
