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, 2001
Filed:
May. 04, 1999
Applicant:
Inventor:
Takanobu Takeuchi, Tokyo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03K 5/08 ; H03L 5/00 ;
U.S. Cl.
CPC ...
H03K 5/08 ; H03L 5/00 ;
Abstract
A semiconductor integrated circuit has an amplifier circuit for amplifying a voltage change accompanying a change in a capacitance of a capacitor in an electric microphone. The integrated circuit includes a voltage conversion circuit for voltage converting this voltage change; an amplifier for amplifying a voltage converted by the voltage conversion circuit; and a reference bias circuit for producing and outputting a reference bias voltage to the amplifier. The voltage conversion circuit operates so that the midpoint of the voltage change is a value approximately ½ the dc voltage supplied to the amplifier.