Analog successive approximation (SAR) analog-to-digital converter (ADC)
First Claim
1. A communication system, comprising:
- phone line side circuitry capable of being coupled to phone lines;
powered side circuitry capable of being coupled to said phone line side circuitry through an isolation barrier; and
an analog-to-digital converter within said phone line side circuitry including a plurality of comparators having outputs that make up a multiple-bit digital value to be transmitted across said isolation barrier,wherein the multiple-bit digital value is indicative of phone line status information.
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Abstract
An analog successive approximation (SAR) analog-to-digital converter (ADC) is disclosed that is a compromise between a SAR ADC implementation and a fully parallel thermometer-to-binary ADC. The analog SAR ADC utilizes N comparators for N bits of output and does not require a clock system, control logic, decode logic, or thermometer-to-binary decode circuitry. Conversion speed is determined by the comparator rate, and the comparator outputs may be used directly as the ADC outputs. The analog SAR ADC disclosed is a low complexity, low-precision analog-to-digital converter (ADC) that may be used to digitize phone line status information so that it may be communicated across a isolation barrier as digital information.
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Citations
33 Claims
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1. A communication system, comprising:
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phone line side circuitry capable of being coupled to phone lines; powered side circuitry capable of being coupled to said phone line side circuitry through an isolation barrier; and an analog-to-digital converter within said phone line side circuitry including a plurality of comparators having outputs that make up a multiple-bit digital value to be transmitted across said isolation barrier, wherein the multiple-bit digital value is indicative of phone line status information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for converting an analog signal into a digital value in a communication system capable of being connected to phone lines, comprising:
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coupling an isolation barrier between powered side circuitry and phone line side circuitry capable of being connected to phone lines; receiving an analog signal, the analog signal being indicative of phone line status information within said phone line side circuitry; and converting said analog signal to a multiple-bit digital value utilizing a plurality of comparators having outputs that make up said multiple-bit digital value. - View Dependent Claims (11, 12, 13)
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14. An analog successive approximation (SAR) analog-to-digital converter (ADC) for digitizing an analog signal, comprising:
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reference circuitry; a plurality of comparators coupled to said reference circuitry and an input signal and having outputs that make up a multiple-bit digital output value; and at least one of said plurality of comparators having an output coupled to said reference circuitry to control in part a reference signal received by another of said plurality of comparators. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for converting an analog signal into a digital value, comprising:
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receiving an analog signal; generating a plurality of reference signals and applying them to a plurality of comparators having outputs that make up a multiple-bit digital value; controlling in part a reference signal received by at least one of said plurality of comparators with an output from another of said plurality of comparators; and converting said analog signal to said multiple-bit digital value utilizing said plurality of comparators. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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Specification