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:
Mar. 22, 2005
Filed:
Jul. 15, 2002
Andrew C. Krochmal, Plymouth, MI (US);
John E. Whitecar, Plymouth, MI (US);
Robert K. Cadena, Dearborn, MI (US);
Gregory R. Hamel, Livonia, MI (US);
Andrew C. Krochmal, Plymouth, MI (US);
John E. Whitecar, Plymouth, MI (US);
Robert K. Cadena, Dearborn, MI (US);
Gregory R. Hamel, Livonia, MI (US);
Visteon Global Technologies, Inc., Dearborn, MI (US);
Abstract
The presence or absence of a speaker connected to an output terminal of an audio system is determined based on the electro-generator properties of the speaker. The audio system includes an output amplifier coupled to the output terminal. The method includes driving the output amplifier with a predetermined drive signal sufficient to produce a predetermined speaker excursion if a speaker is connected to the output terminal. The output amplifier is then isolated from the output terminal. A signal at the output terminal is sensed after the output amplifier is isolated. The sensed signal is compared with a predetermined reference for determining whether a speaker back-EMF is present. A speaker detection signal is generated indicating absence of a speaker if the back-EMF is not present.