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:
Aug. 19, 2003

Filed:

Dec. 18, 1998
Applicant:
Inventors:

John M. Muza, Plano, TX (US);

Roberto Sadkowski, Plano, TX (US);

Martin Sallenhag, Lund, SE;

Heino Wendelrup, Malmoe, SE;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04R 3/00 ;
U.S. Cl.
CPC ...
H04R 3/00 ;
Abstract

A microphone bias current detection circuit includes: a microphone circuit ; an amplifier having a first output and a second output, the first output is coupled to the microphone circuit for providing a bias current to the microphone circuit , the second output provides a sampled current I proportional to the bias current; a first switch having a first end coupled to the second output of the amplifier ; a resistor having a first end coupled to a second end of the first switch ; and a second switch coupled between the first end of the resistor and a reference current source.


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