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:
Jul. 18, 2006
Filed:
Oct. 12, 2004
Lars Risbo, Copenhagen, DK;
James Teng, Dallas, TX (US);
Lars Risbo, Copenhagen, DK;
James Teng, Dallas, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A class AD audio amplifier system () with DC output detection logic () is disclosed. The amplifier system () includes multiple audio channels (), each of which includes a pulse-width-modulator (PWM) (). The DC detection logic () includes a sigma-delta modulator () and a digital low-pass filter () that monitors the PWM output signals from the PWM modulators (). The sigma-delta modulator () operates at a first clock frequency, while the low-pass filter () operates at a much lower clock frequency, so that AC audio components, PWM harmonics, and sigma-delta quantization error is suppressed from the DC detection. The modulated filtered signal is compared against a threshold level (THRSH) to determine whether the amplitude of a DC component at the PWM output is sufficiently high to constitute a fault. If so, a fault detection signal (DC_DET) is issued, and the PWM modulators () are disabled to prevent unsafe conditions in the system ().