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:
Oct. 29, 2019
Filed:
Sep. 27, 2016
Texas Instruments Incorporated, Dallas, TX (US);
Ball Fan, Tianjin, CN;
Wenpang David Wang, Allen, TX (US);
Christopher Michael Graves, Sherman, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
An audio accessory key detection system () includes a host circuit (-) coupled to communicate via a microphone line () with an accessory circuit (-) in either a MSFT mode or a digital communication mode. Depletion mode transistors (-) in the accessory circuit are coupled between keys (-) of the accessory circuit, respectively. The depletion mode transistors are allowed to remain conductive for MSFT mode operation. For digital communications mode operation, the host circuit sends a command via the microphone line to a key detector and controller circuit (A) in the accessory circuit. In response, a voltage is generated to turn the depletion mode transistors off so as to allow digital communications mode operation between the accessory circuit and the host circuit.