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.

Date of Patent:
Jan. 21, 2003

Filed:

May. 11, 2000
Applicant:
Inventors:

Motohiko Morita, Nagareyama, JP;

Kenji Maio, Tokyo, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03M 1/66 ;
U.S. Cl.
CPC ...
H03M 1/66 ;
Abstract

In a DA converter wherein an analog output voltage is formed in such a way that constant currents formed by a plurality of constant-current source transistors are selectively fed to a load resistor by controlling switching means to turn ON and OFF in correspondence with input signals; each of the constant-current source transistors is operated in an operating range from a saturation region to a non-saturation region as the output voltage enlarges in its absolute value, and those of the plurality of constant-current source transistors whose currents based on the operations in the non-saturation regions are selected by the switching means have their sizes enlarged so as to compensate for current decrements ascribable to such operations in the non-saturation regions.


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