Tuning and DAC Selection of High-Pass Filters for Audio Codecs
AssigneeConexant Systems, Inc.
InventorsChristian Larsen, Lorenzo Crespi, Mouna Elkhatib
Life of this patent
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Abstract
An integrated audio codec includes a high-pass filter to prevent damage to personal computer speakers and other components. The audio codec may be compliant with HD audio standards and can operate with generic software drivers. Tuning of the high-pass filter is provided through an external pin-out where either an external capacitor or external resistors provide an ability to tune the high-pass filter. In one implementation, a tuning voltage is digitized into a tuning code used by a digital high-pass filter. In addition, multiplexers can be used to insure only the audio path leading to the speakers is filtered.
Claims20
An integrated audio driver comprising:
- a digital high-pass filter operable to receive a digital audio signal to produce a filtered digital audio signal;
- a digital to audio converter (DAC) operable to receive the filter digital audio signal from the digital high-pass filter and to produce an analog audio signal;
- a speaker driver operable to receive the analog audio signal and to produce a signal to drive a speaker;
- and
- a control circuit operable to receive tuning information from a integrated circuit pin-out and to configure the digital high-pass filter on the basis of the tuning information.
An integrated audio driver comprising:
- a digital to audio converter (DAC) operable to receive a digital audio signal to produce an analog audio signal;
- an portion of an analog filter coupled to an external capacitor, wherein the portion of the analog filter and the external capacitor comprise the analog filter which is operable to receive the analog audio signal and produced a filtered analog audio signal;
- a speaker driver operable to receive the filtered analog audio signal and to drive a speaker.
A method in a single integrated circuit comprising:
- filtering a digital audio signal with a digital high-pass filter;
- converting the digital audio signal to an analog audio signal;
- driving a speaker with the analog audio signal;
- receiving tuning information from an integrated circuit pin-out;
- and
- tuning the digital high-pass filter based on the tuning information.
Dependencies are inferred from the claim text.