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:
May. 23, 2000
Filed:
Jun. 24, 1998
Fumihiko Kato, Yamagata, JP;
NEC Corporation, Tokyo, JP;
Abstract
A digital-to-analog converter has a single capacitor array having plural weighted capacitors, a first capacitor connected between an output node of an operational amplifier and an inverted input node of the operational amplifier and a second capacitor both connected to the inverted input node, and a pulse signal, a polarity control signal maintained in one of the high level and the low level over each pulse period of the pulse signal and a multi-bit digital signal are supplied to a controller; the controller causes a switching unit to selectively supply a first reference voltage and a second reference voltage to the weighted capacitors depending upon the logic level of the data bits of the digital signal and, thereafter, a third reference voltage to the weighted capacitors in a certain pulse period, and the switching unit carries out the switching action in the opposite order to the previous pulse period so that the operational amplifier varies an analog output signal with respect to a potential level supplied to the non-inverted input node thereof.