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:
Dec. 21, 1993
Filed:
Nov. 12, 1991
Pierre Austruy, Nice, FR;
Jean-Paul Conjeaud, Antibes, FR;
Patrick Massi, St. Laurent du Var, FR;
Christian Jacquart, Gattieres, FR;
International Business Machines Corporation, Armonk, NY (US);
Abstract
A hot plug circuit insuring that the plugging of cards to a board is performed in the hot-plug mode when the cards are supplied from a common power supply located on one of the cards or on the board. This circuit (62) limits the surge current generated at the interconnection of first circuits (30) arranged on a first card (1) and powered by a supply device (2) providing a first supply voltage (ground) on a first supply line (36) and a second supply voltage (+V) on a second supply line (34), with second circuit (24) on a second card powered by the supply device (2) through a third supply line (74) and fourth supply line (76). The surge current results from the charge of a decoupling capacitor of capacitance Cd arranged on the second card between the third and fourth supply lines when the cards are interconnected through an interconnecting arrangement (14, 12, 22). The hot plug circuit comprises a controlled ramp generation device connected to the first and second supply lines and activated when the connection between the first and third supply line is completed through the connecting arrangement to start the generation on the fourth supply line of a first ramp voltage Vb derived from the voltages on the first and second supply lines, said ramp voltage having an adjustable slope a=dVb/dt, whereby the surge current i which is equal to a.Cd can be limited to a desired value by adjusting the slope value a.