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:
Apr. 17, 1990
Filed:
Feb. 13, 1989
Sing W Chin, Alameda, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A novel multistep flash analog to digital converter is taught, including a voltage estimator which quickly provides a rough estimate of the analog input signal. This rough estimate is used to select appropriate reference voltage tap points for use in the first flash conversion. This first flash conversion, together with the voltage estimate, provides the most significant bits of the digital output word. A digital to analog converter is used to provide a residual voltage which is then converted by a second operation of the flash converter, thereby providing the least significant bits of the digital output word. In one embodiment, the voltage estimate is performed at the same time that the analog input signal is sampled by the flash converter in preparation for the first flash conversion. Therefore, speed of operation is not degraded by the addition of the voltage estimator.