A/D converter with minimized transfer error
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Accused Products
Abstract
An A/D converter has at least one converter stage which, respectively, has a sample and hold circuit for sampling an analog input signal. The converter stage also includes a comparator unit that compares the analog input signal with a reference value in order to produce a digital output value from the converter stage, a digital/analog converter for converting the digital output value into an analog signal, a subtractor for subtracting the analog signal from the sampled input signal, a signal amplifier for amplifying the output signal which is output by the subtractor with a particularl singal gain factor for the next converter stage, and a weighting unit for multiplying the digital output value by a multiplier for addition to further weighted output values from converter stages to produce the digital output value from the A/D converter.
20 Citations
32 Claims
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1-14. -14. (canceled)
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15. An analog to digital converter comprising:
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a sample and hold circuit operable to sample an input signal;
a comparator unit operable to compare the input signal to a reference signal, and to provide a digital output value based upon the comparison;
a digital to analog converter (DAC) including a calibration capacitor and a plurality of DAC capacitors, the DAC operably connected to the comparator unit to receive the digital output value, the DAC operable to convert the digital output value into an analog signal;
a subtractor operably connected to receive the sampled input from the sample and hold circuit and the digital output value from the DAC, the subtractor operable to subtract the analog signal from the sampled input signal and to generate a remainder based thereon;
an amplifier operably connected to receive the remainder from the subtractor and operable to output an amplified remainder based upon the remainder;
a weighting unit operable to receive the digital output value from the comparator and operable to provide a weighted digital output value by multiplying the digital output with a received multiplier signal;
a switch device operable to switch a received calibration signal to the calibration capacitor and further to each of the plurality of DAC capacitors; and
a calibration unit operably connected to receive the calibration signal and the output of the amplifier and operable to control the switch device and to calculate the respective signal gains of each of the plurality of DAC capacitors in order to calculate information representative of a transfer error. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. An analog to digital pipeline converter comprising:
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a digital to analog converter (DAC) including a plurality of DAC capacitors and a calibration capacitor, the DAC operable to receive an analog signal; and
a switching device switchably connected to the plurality of DAC capacitors and the calibration capacitor, the switching device operable to switchably connect the output of a random signal generator to the calibration capacitor and further to each of the plurality of DAC capacitors, such that when a random signal from the random signal generator is applied to the calibration capacitor and further to each of the plurality of DAC capacitors, respectively, the output from the digital to analog converter is indicative of the gain of the calibration capacitor and further each of the plurality of DAC capacitors, respectively. - View Dependent Claims (29, 30, 31, 32)
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Specification