Audio input-output module, plug-in detection module and methods for use therewith

1. An audio input-output module comprising:

a plurality of plug-in receptors, each of the plurality of plug-in receptors having a corresponding plurality of switches that have a first state when coupled to a plug connector and a second state when plug-in receptor is decoupled from the plug connector;

an impedance network, operably coupled to the plurality of switches, for producing a plug-in signal in response to a supply signal that varies based on whether each of the plurality of switches is in the first state or the second state;

a reference signal generator for generating a reference signal having a plurality of reference signal values;

a comparator, operably coupled to the plug-in signal and the reference signal, for generating a detection signal when the plug-in signal compares favorably to the reference signal, wherein the comparator includes a first input current and a second input current and wherein the comparator further includes an offset cancellation module for automatically balancing the first input current and the second input current that includes a first offset current generator for generating a first offset current having a plurality of first offset current values;

a processing module, operably coupled to the detection signal, the first offset current generator and the reference signal, for detecting which of the plurality of plug-in receptors have a plug connector coupled thereto, and further for controlling the first offset current generator to generate a sequence of first offset current values, and controlling the first offset current generator to hold the first offset current value when the first input current compares favorably to the second input current; and

a switch network for selectively coupling an audio output to one of the plurality of plug-in receptors.

2. The audio input-output module of claim 1 wherein first offset current has a first polarity and the offset cancellation module includes:

a second offset current generator for generating a second offset current having a plurality of first offset current values of a second polarity;

wherein the processing module is operably coupled to the second offset current generator, and wherein the processing module is further operable to control the second offset current generator to generate a sequence of second offset current values, and control the second offset current generator to hold the second offset current value when the first input current compares favorably to the second input current.

3. The audio input-output module of claim 1 wherein the sequence of first offset current values and the sequence of second offset current values are scanned simultaneously until the first input current compares favorably to the second input current.

4. The audio input-output module of claim 1 wherein the plurality of plug-in receptors include four or more jacks for coupling an audio module to at least one of: an audio line input, and audio line output, a video input, a video output, a headphone, and a microphone.

5. The audio input-output module of claim 1 wherein the impedance network includes a resistive voltage divider.

6. The audio input-output module of claim 5 wherein the resistive voltage divider includes a plurality of high accuracy resistors.

7. The audio input-output module of claim 1 wherein the reference signal generator generates a reference signal value sequence that includes the plurality of reference signal values.

8. The audio input-output module of claim 7 wherein the reference signal generator includes a multi-tap resistive voltage divider, and selection module for selecting a sequence of voltage divider taps.

9. The audio input-output module of claim 1 wherein the processing module detects which of the plurality of plug-in receptors have a plug connector coupled thereto by determining one of the plurality of reference signal values when the plug-in signal compares favorably to the reference signal, and by indexing one of the plurality of reference signal values to a look-up table.

10. The audio input-output module of claim 1 wherein at least one of: the reference signal generator, the comparator, the audio output driver and the processing module, is implemented as part of a system on a chip integrated circuit.

11. The audio input-output module of claim 1 wherein the switch network is further operable to selectively receive an audio input from one of the plurality of plug-in receptors.

12. A plug-in detection module comprising:

an impedance network for producing a plug-in signal in response to a supply signal that varies when one of a plurality of plug-in receptors is coupled to a plug connector and when one of the plurality of plug-in receptors is decoupled;

a reference signal generator for generating a reference signal having a plurality of reference signal values;

a comparator, operably coupled to the plug-in signal and the reference signal, for generating a detection signal when the plug-in signal compares favorably to the reference signal, wherein the comparator includes a first input current and a second input current and wherein the comparator further includes an offset cancellation module for automatically balancing the first input current and the second input current that includes a first offset current generator for generating a first offset current having a plurality of first offset current values;

a processing module, operably coupled to the detection signal, the first offset current generator and the reference signal, for detecting which of the plurality of plug-in receptors have a plug connector coupled thereto, and further for controlling the first offset current generator to generate a sequence of first offset current values, and controlling the first offset current generator to hold the first offset current value when the first input current compares favorably to the second input current.

13. The plug-in detection module of claim 12 wherein first offset current has a first polarity and the offset cancellation module includes:

a second offset current generator for generating a second offset current having a plurality of first offset current values of a second polarity;

wherein the processing module is operably coupled to the second offset current generator, and wherein the processing module is further operable to control the second offset current generator to generate a sequence of second offset current values, and control the second offset current generator to hold the second offset current value when the first input current compares favorably to the second input current.

14. The audio input-output module of claim 12 wherein the sequence of first offset current values and the sequence of second offset current values are scanned simultaneously until the first input current compares favorably to the second input current.

15. The plug-in detection module of claim 12 wherein the plurality of plug-in receptors include four or more jacks for coupling an audio module to at least one of: an audio line input, and audio line output, a video input, a video output, a headphone, and a microphone.

16. The plug-in detection module of claim 12 wherein the impedance network includes a resistive voltage divider.

17. The plug-in detection module of claim 16 wherein the resistive voltage divider includes a plurality of high accuracy resistors.

18. The plug-in detection module of claim 12 wherein the reference signal generator generates a reference signal value sequence that includes the plurality of reference signal values.

19. The plug-in detection module of claim 18 wherein the reference signal generator includes a multi-tap resistive voltage divider, and selection module for selecting a sequence of voltage divider taps.

20. The plug-in detection module of claim 12 wherein the processing module detecting which of the plurality of plug-in receptors have a plug connector coupled thereto by determining one of the plurality of reference signal values when the plug-in signal compares favorably to the reference signal, and by indexing one of the plurality of reference signal values to a look-up table.

21. The plug-in detection module of claim 12 wherein at least one of: the reference signal generator, the comparator, and the processing module, is implemented as part of a system on a chip integrated circuit.

22. A method comprising:

producing a plug-in signal in response to a supply signal, wherein the plug-in signal varies when each of a plurality of plug-in receptors is coupled to a plug connector and when each of the plurality of plug-in receptors is decoupled;

generating a reference signal having a plurality of reference signal values;

generating a detection signal when the plug-in signal compares favorably to the reference signal via a comparator that includes a first input current and a second input current that are automatically balanced by:

generating a sequence of first offset current values to offset the first input current; and

holding the first offset current value when the first input current compares favorably to the second input current; and

detecting which of the plurality of plug-in receptors have a plug coupled thereto based on the reference signal and the detection signal.

23. The method of claim 22 wherein the plurality of plug-in receptors include four or more jacks for coupling an audio module to at least one of: an audio line input, and audio line output, a video input, a video output, a headphone, and a microphone.

24. The method of claim 22 wherein the step of generating a reference signal includes generating a reference signal value sequence that includes the plurality of reference signal values.

25. The method of claim 22 wherein the step of detecting which of the plurality of plug-in receptors have a plug coupled thereto includes:

determining one of the plurality of reference signal values when the plug-in signal compares favorably to the reference signal; and

indexing one of the plurality of reference signal values to a look-up table.