ANALOG/DIGITAL CONVERTER AND METHOD FOR CONVERTING ANALOG SIGNALS TO DIGITAL SIGNALS
First Claim
1. A cyclic-type analog-digital converter for converting an analog input signal that is input into a digital signal having a predetermined resolution, the analog-digital converter comprising:
- a digital approximator including a comparator configured to compare the magnitude of a first analog signal that is input and a threshold value and to output a digital value indicative of the comparison result and a multiplying digital-analog converter configured to amplify the first analog signal by a factor of β and
at the same time, to perform a predetermined calculation in accordance with the comparison result of the comparator to output a second analog signal;
a multiplexer configured to output an analog input signal as the first analog signal when calculating the most significant bit and to output the second analog signal as the first analog signal when calculating a bit other than the most significant bit;
a β
estimator configured to estimate the value of β
; and
a digital signal output unit configured to sequentially take in the digital value output from the comparator and to output the digital value as a digital signal based on an estimated value of β
, whereinthe value of β
is a value larger than 1 and smaller than 2.
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Accused Products
Abstract
The objective of the invention is to provide an A/D converter that exhibits fewer malfunctions due to variations in manufacturing. An A/D converter (1) of the invention, which is a cyclic type of analog/digital converter for converting an analog input signal to a digital signal having a predetermined resolution, comprises: a digital approximation unit (10) that includes a comparing unit (13) for comparing the magnitude of an input first analog signal with a threshold value to output a digital value indicating a result of the comparison and that also includes an MDAC unit (14) for amplifying the first analog signal to β-fold, where β is greater than one but smaller than two, and for executing a predetermined computation in accordance with the result of the comparison of the comparing unit to output a second analog signal; a multiplexer (20) that, if the MSB is to be computed, outputs the analog input signal and, otherwise, outputs the second analog signal as the first analog signal; a β estimating unit (30) that estimates the value of β; and a digital signal outputting unit (40) that sequentially takes in digital values outputted by the comparing unit and that outputs the taken-in digital values as the digital signal.
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Citations
16 Claims
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1. A cyclic-type analog-digital converter for converting an analog input signal that is input into a digital signal having a predetermined resolution, the analog-digital converter comprising:
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a digital approximator including a comparator configured to compare the magnitude of a first analog signal that is input and a threshold value and to output a digital value indicative of the comparison result and a multiplying digital-analog converter configured to amplify the first analog signal by a factor of β and
at the same time, to perform a predetermined calculation in accordance with the comparison result of the comparator to output a second analog signal;a multiplexer configured to output an analog input signal as the first analog signal when calculating the most significant bit and to output the second analog signal as the first analog signal when calculating a bit other than the most significant bit; a β
estimator configured to estimate the value of β
; anda digital signal output unit configured to sequentially take in the digital value output from the comparator and to output the digital value as a digital signal based on an estimated value of β
, whereinthe value of β
is a value larger than 1 and smaller than 2. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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2. A pipeline-type analog-digital converter for converting an analog input signal that is input to an input terminal into a digital signal having a predetermined resolution, the analog-digital converter comprising:
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a plurality of digital approximators including a comparator configured to compare the magnitude of a first analog signal that is input and a threshold value and to output a digital value indicative of the comparison result and a multiplying digital-analog converter configured to amplify the first analog signal by a factor of β and
at the same time, to perform a predetermined calculation in accordance with the comparison result of the comparator to output a second analog signal, the plurality of digital approximators being connected in series to the input terminal and the second analog signal of the digital approximator in the previous stage being provided to the digital approximator in the subsequent stage as the first analog signal;a β
estimator configured to estimate the values of β
of the plurality of digital approximators; anda digital signal output unit configured to sequentially take in the digital value output from the comparator and to output the digital value as a digital signal based on an estimated value of β
, whereinthe value of β
is a value larger than 1 and smaller than 2. - View Dependent Claims (12, 13)
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14. A method for estimating a value of an amplification degree of β
- of an analog-digital converter comprising a multiplying digital-analog converter whose amplification degree is β and
having a predetermined resolution, the method comprising the steps of;inputting the same estimation input DC signal to the analog-digital converter; converting the input signal into two β
-adic digital signals; andestimating the value of the amplification degree of β
based on a plurality of converted β
-adic digital signals, whereinthe value of β
is a value larger than 1 and smaller than 2, andthe number of bits of the plurality of converted β
-adic digital signals is specified so that the resolution in the case where the value of β
is the value in the worst-case design is substantially equal to the predetermined resolution. - View Dependent Claims (15, 16)
- of an analog-digital converter comprising a multiplying digital-analog converter whose amplification degree is β and
Specification