Patent Application
20050242975
The present invention is method whereby digital audio devices derive their power directly from the incoming signal, utilizing both hardware and software protocol techniques.
Audio speakers, including headphones, are typically driven by stand-alone amplifiers which often utilize external power supplies. Especially in the case of headphones, this approach can be cumbersome, particularly as digital sources facilitate integration. Furthermore, digital audio sources, such as digital microphones, often retain power supply complexity of earlier analog counterparts.
There exists a need of a simple self-contained method whereby audio input/output devices may be powered by their input or output data streams.
The present invention provides an integrated speaker or microphone which derives its power from an incoming signal, thereby minimizing or eliminating the need for an external amplifier or power supply.
In terms of apparatus, a self-powered digital audio system according to the invention includes an audio transducer, an input for receiving a digital audio signal, an amplifier for amplifying the digital audio signal to or from the audio transducer, and a rectifier for rectifying the digital audio signal for use in powering the amplifier. A filter may be included for filtering the output of the rectifier. In the preferred embodiment, the digital audio signal uses a non-return-to-zero (NRZ) encoding scheme. When the transducer is a microphone, it is connected to an analog-to-digital (A/D) converter, also powered by the rectified digital audio signal.
The output of analog-to-digital converter 107 drives the control input of switching device 106, which selectively shunts wire 103 to 102. It is assumed that the receiving device connected to connector 101 provides limited DC current to wire 102, allowing wire 102 to switch between two voltage states under control of switching device 106. In order to limit low-frequency fluctuations on the supply voltage supplied by diode 104, a non-return-to-zero (NRZ) encoding scheme is used by analog-to-digital converter 107.
Assuming the existence of positive-going data pulses on wires 101 and 202, it can be seen by the above explanations that the data stream carried by wires 101 and 202 is used to directly provide power to the appropriate audio input/output devices. Although single-channel embodiments are disclosed, those of skill in the art of digital audio will readily appreciate that multiple-channel instances of the invention will function by extrapolation.
I claim:
This application claims priority to U.S. Provisional Patent Application Ser. No. 60/562,760, filed Apr. 14, 2004, the entire content of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60562760 | Apr 2004 | US |
