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:
Nov. 01, 2005
Filed:
Jul. 21, 2003
Michael John Erickson, Loveland, CO (US);
Richard K. Brush, Los Altos, CA (US);
Michael John Erickson, Loveland, CO (US);
Richard K. Brush, Los Altos, CA (US);
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
An apparatus and method for indicating and allowing hot swapping of a circuit board. During both insertion and extraction of a circuit board from a system, two inputs signals are generated from staggered pins located on the circuit board's connector. The inputs are processed through a NAND function implemented with transistors and output to two Schmitt trigger inverters connected in series. The output of the series connection of Schmitt trigger inverters goes high when both input signals are high and goes low when one of the inputs signals goes low. In addition, through the use of a resistor, capacitor combination connected to the input of the first Schmitt trigger inverter, the output signal remains high for a period of time after one of the input signals goes low. This additional period of time prevents any damage or disruption of signaling caused by transient current and voltage fluctuations as a circuit board is inserted or extracted. The output signal can be used in both single-ended and differential SCSI applications.