PLD mit einem Konfigurationsspeicher mit Aushilfsstromversorgung, und Verfahren für die Stromversorgung eines PLDs mit Konfigurationsspeicher

摘要

A programmable logic integrated circuit device utilizes volatile memory elements such as SRAM (62) for retaining configuration information. A circuit (66) is provided as part of the device for detecting loss of power on a supply input pin (64). When power loss is detected, a backup voltage supply (70), packaged with the programmable logic device as a unit, is connected thereto. The backup power is used to supply voltage only to those portions of the device having volatile memory elements containing configuration information. Backup power is not provided to input and output buffers (74,76) of the device, thereby preventing excess loads being placed upon the backup device because of events which may occur external to the programmable logic device.