Browse Prior Art Database

Method for an add-in card to utilize either a locally generated or a system generated voltage reference

IP.com Disclosure Number: IPCOM000010029D
Publication Date: 2002-Oct-09
Document File: 2 page(s) / 842K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an add-in card to utilize either a locally generated or a system generated voltage reference. Benefits include improved performance and improved design flexibility.

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Method for an add-in card to utilize either a locally generated or a system generated voltage reference

Disclosed is a method for an add-in card to utilize either a locally generated or a system generated voltage reference. Benefits include improved performance and improved design flexibility.

Background

        � � � � � Graphics and memory controller hubs (GMCHs) can make use of a multiplexed digital video out (DVO) interface and an accelerated graphics port (AGP) interface. This hardware enables the systems to support either AGP or AGP digital display (ADD) cards in the AGP connector.

        � � � � � AGP connectors provide a pathway for the motherboard to supply a reference voltage, designated as VrefCG, to the card and a reference, designated as VrefGC, from the card back to the motherboard. ADD cards plugged into AGP connectors must meet the same reference supply requirements as an AGP card.

        � � � � � DVO devices that reside on ADD cards may have differing tolerances for their voltage reference supply. Some may be tied to the motherboard’s voltage to track the noise generated by chips (such as the GMCH) on the motherboard. Others may require a local voltage supply for quality and reliability.

        � � � � � Card/device manufacturers must conventionally choose from the outset the referencing scheme they want to utilize.

Description

        � � � � � The disclosed method is circuitry on an add-in card (module) that enables vendors to select from a locally generated voltage supply or a system-generated supply for a reference voltage. The circuit design meets the VrefCG and VrefGC requirements of the AGP cards. The method provides a cost-effective solution by...