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:
Oct. 26, 1999
Filed:
May. 29, 1998
Bernard Lee Morris, Emmaus, PA (US);
Bijit Thakorbhai Patel, Breinigsville, PA (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
An integrated, low power bus holder circuit implemented in low voltage technology is capable of interfacing with a relatively high voltage bus. In an illustrative embodiment, the bus holder circuit includes a first inverter for inverting a logic voltage present on a data bus and a second inverter for inverting the output of the first inverter. The second inverter is comprised of a series string of first and second pFETS and first and second nFETS, with the gates of the first pFET and first nFET coupled to the output of the first inverter. The data bus is coupled to a first circuit node between the second nFET and second pFET, and the bus logic level is maintained thereat. A third pFET is coupled to the second inverter and conducts current when a high logic voltage is present on the bus. A resistance device is coupled between a drain of the third pFET and a point of low reference potential. Advantageously, the circuit arrangement of the illustrative embodiment does not draw any DC power since it avoids the use of a separate, DC power consuming biasing circuit to bias the third pFET. A fourth pFET is preferably employed to eliminate leakage current in the first inverter.