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:
Jul. 27, 1993
Filed:
Jan. 10, 1992
Yasuo Yagi, Tokyo, JP;
Pioneer Electric Corporation, Tokyo, JP;
Abstract
A digital-to-analog converter has a plurality of switches, each of which being responsive to a bit of a digital signal having n bits, to selectively pass therethrough a weighted current having a magnitude of 2.sup.i-1 Ic where i is an ith bit. The respective weighted current flows through a corresponding transistor into a resistor ladder circuit. The resistor ladder circuit has a plurality of arms, each of which receive a weighted current from the emitter of a corresponding transistor. The digital-to-analog converter further includes a plurality of base resistors connected in series such that the bases of the transistors are connected with corresponding junctions of the base resistors r1-r7. The plurality of base resistors carry a first current therethrough. A current control circuit BC for controlling the first current through the series-connected base resistors to maintain emitter voltages of two predetermined transistors of the plurality of transistors such that the emitter voltages of the two predetermined transistors are always the same.