A-D CONVERTER AND A-D CONVERT METHOD
First Claim
1. An A/D converter that outputs a digital output signal obtained by digitalizing an analog input signal, comprising:
- a bit selecting section that selects a conversion object bit from a high-order bit to a low-order bit of the digital output signal in order;
a threshold-value controlling section that determines a threshold data expressing a boundary value between zero and one of the conversion object bit on the basis of an already-determined value of a higher-order bit than the conversion object bit;
a D/A converting section that digital-to-analog converts the threshold data and generates an analog threshold value;
a comparing section that compares, at a plurality of different timings in a conversion time interval determining a value of the conversion object bit, the analog input signal and the analog threshold value and outputs a plurality of comparison results at the timings; and
a bit determining section that determines the value of the conversion object bit on the basis of the plurality of comparison results.
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Accused Products
Abstract
There is provided an A/D converter that outputs a digital output signal obtained by digitalizing an analog input signal. The A/D converter includes a bit selecting section that selects a conversion object bit from a high-order bit to a low-order bit of the digital output signal in order, a threshold-value controlling section that determines a threshold data expressing a boundary value between zero and one of the conversion object bit, a D/A converting section that digital-to-analog converts the threshold data and generates an analog threshold value, a comparing section that compares, at a plurality of different timings in a conversion time interval determining a value of the conversion object bit, the analog input signal and the analog threshold value and outputs a plurality of comparison results at the timings, and a bit determining section that determines the value of the conversion object bit.
39 Citations
11 Claims
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1. An A/D converter that outputs a digital output signal obtained by digitalizing an analog input signal, comprising:
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a bit selecting section that selects a conversion object bit from a high-order bit to a low-order bit of the digital output signal in order; a threshold-value controlling section that determines a threshold data expressing a boundary value between zero and one of the conversion object bit on the basis of an already-determined value of a higher-order bit than the conversion object bit; a D/A converting section that digital-to-analog converts the threshold data and generates an analog threshold value; a comparing section that compares, at a plurality of different timings in a conversion time interval determining a value of the conversion object bit, the analog input signal and the analog threshold value and outputs a plurality of comparison results at the timings; and a bit determining section that determines the value of the conversion object bit on the basis of the plurality of comparison results. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An A/D converter that outputs a digital output signal obtained by digitalizing an analog input signal, comprising:
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a plurality of comparators of which each compares the analog input signal and an analog threshold value according to a specified digital threshold data; a high-order field determining section that narrows down a data value corresponding to a high-order field for a predetermined bit number in the digital output signal on the basis of a plurality of comparison results obtained by supplying different threshold data to the plurality of comparators; a low-order field computing section that computes a plurality of candidate values for a data value corresponding to a low-order field for a predetermined number of bits located at a side lower than the high-order field by means of the plurality of comparators; a low-order field determining section that determines the data value corresponding to the low-order field on the basis of the plurality of candidate values; and a timing controlling section that causes, when computing the plurality of candidate values of the data value corresponding to the low-order field, a first comparator among the plurality of comparators to compare the analog input signal and the analog threshold value at a first timing in a conversion time interval determining a value for one bit and causes a second comparator among the plurality of comparators to compare the analog input signal and the analog threshold value at a second timing different from the first timing in the conversion time interval.
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10. An A/D convert method for outputting a digital output signal obtained by digitalizing an analog input signal, comprising:
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selecting a conversion object bit from a high-order bit to a low-order bit of the digital output signal in order; determining a threshold data expressing a boundary value between zero and one of the conversion object bit on the basis of an already-determined value of a higher-order bit than the conversion object bit; digital-to-analog converting the threshold data and generating an analog threshold value; comparing, at a plurality of different timings in a conversion time interval determining a value of the conversion object bit, the analog input signal and the analog threshold value and outputting a plurality of comparison results at the timings; and determining the value of the conversion object bit on the basis of the plurality of comparison results.
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11. An A/D convert method for outputting a digital output signal obtained by digitalizing an analog input signal, comprising:
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narrowing down a data value corresponding to a high-order field for a predetermined bit number in the digital output signal on the basis of a plurality of comparison results obtained by supplying different threshold data to a plurality of comparators of which each compares the analog input signal and an analog threshold value according to a specified digital threshold data; computing a plurality of candidate values for a data value corresponding to a low-order field for a predetermined number of bits located at a side lower than the high-order field by means of the plurality of comparators; determining the data value corresponding to the low-order field on the basis of the plurality of candidate values; and causing, when computing the plurality of candidate values of the data value corresponding to the low-order field, a first comparator among the plurality of comparators to compare the analog input signal and the analog threshold value at a first timing in a conversion time interval determining a value for one bit and causing a second comparator among the plurality of comparators to compare the analog input signal and the analog threshold value at a second timing different from the first timing in the conversion time interval.
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Specification