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:
Feb. 14, 1995

Filed:

Jul. 15, 1993
Applicant:
Inventor:

Kiyoshi Fukushima, Kumamoto, JP;

Assignee:

NEC Corporation, Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03M / ;
U.S. Cl.
CPC ...
341120 ; 341141 ; 341155 ; 341172 ;
Abstract

Disclosed herein is a microcomputer having a test circuit for an A/D converter of a C/R type. This converter includes a resistor circuit having a plurality of resistors connected in series between reference potential points to generate a changeable reference voltage and a capacitor circuit having a plurality of capacitors for storing electrical charges relative to an analog input voltage and to the changeable reference voltage, and the test circuit is coupled to the resistor circuit and the capacitor circuit and further to first and second terminals and activated in a test mode to transfer the changeable reference voltage to the first terminal and another reference voltage, which is produced outside the microcomputer, to the capacitor circuit.


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