Patent Number: 6,683,548

Title: Analog isolation system with digital communication across a capacitivebarrier

Abstract: An isolation system is provided that is suitable for use in telephony,medical instrumentation, industrial process control and otherapplications. Preferred embodiments of the invention comprise a capacitiveisolation barrier across which a digital signal is communicated. Thesystem provides a means of communication across the isolation barrier thatis highly immune to amplitude and phase noise interference. Clock recoverycircuitry may be employed on one side of the isolation barrier to extracttiming information from the digital signal communicated across thebarrier, and to filter the effects of phase noise introduced at thebarrier. Delta-sigma converters may be disposed on both sides of theisolation barrier to convert signals between analog and digital domains.An isolated power supply may also be provided on the isolated side of thebarrier, whereby direct current is generated in response to the digitaldata received across the isolation barrier. Finally, a bidirectionalisolation system is provided whereby bidirectional communication ofdigital signals is accomplished using a single pair of isolationcapacitors. In preferred embodiments, the digital data communicated acrossthe barrier consists of digital delta-sigma data signals multiplexed intime with other digital control, signaling and framing information.

Inventors: Scott; Jeffrey W. (Austin, TX), Sooch; Navdeep S. (Austin, TX), Welland; David R. (Autin, TX)


International Classification: H04M 11/06 (20060101); H04B 14/06 (20060101); H04B 14/02 (20060101); H04L 25/06 (20060101); H04L 7/033 (20060101); H03M 003/02 ()

Expiration Date: 01/22016