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US 5,465,093 AGranted
Analog-to-digital converter
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsKeiichi Kusumoto, Akira Matsuzawa
Life of this patent
Estimating the term…
Abstract
The present invention discloses an improved analog-to-digital converter. A second sampling circuit samples the voltage difference between an analog signal and a reference voltage, before a first sampling circuit moves to a follow operation from a sample operation. Owing to pipelining by the first and second sampling circuits, even after the first sampling circuit moves to a follow operation, the difference between an analog signal and a reference voltage is still applied to a logical-level amplifier. The output of the logical-level amplifier, amplified to a logical voltage, is converted by a logic device into an A/D conversion output. Therefore, ADC differential non linearity error can be reduced.
Claims8
An analog-to-digital converter (ADC) comprising:
- plural sets of first sampling means for sampling an analog input voltage, each set of said first sampling means including a first switch, a first holding capacitor, and an amplifying means for amplifying the voltage difference between a sampled analog input voltage and a reference voltage;
- plural sets of second sampling means for sampling the amplified voltage difference between a sampled analog input voltage and a reference voltage and providing an output voltage for each set of second sampling means, each set of said second sampling means including a second switch, a second holding capacitor;
- logical-level amplifier means for amplifying each said output voltage to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein the output voltages serve as comparison signals for execution of the analog-to-digital conversion.
3 more elements
An ADC comprising;
- first sampling means for sampling an analog input voltage;
- amplifying means for amplifying the voltage difference between a sampled analog input voltage and a reference voltage;
- second sampling means for sampling an output voltage of said amplifying means and providing an output voltage;
- logical-level amplifier means for amplifying the output voltage of said second sampling means to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein said output voltage of said second sampling means serves as a comparison signal for execution of the analog-to-digital conversion.
4 more elements
An ADC comprising;
- first sampling means for sampling an analog input voltage to output the voltage difference between a sampled analog input voltage and a reference voltage;
- subtracting means for subtracting an offset voltage of said first sampling means;
- second sampling means for sampling an output voltage of said amplifying means and providing an output voltage;
- logical-level amplifier means for amplifying the output voltage of said second sampling means to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein said output voltage of said second sampling means serves as a comparison signal for execution of the analog-to-digital conversion.
4 more elements
An ADC comprising;
- first sampling means for sampling an analog input voltage;
- amplifying means for amplifying the voltage difference between a sampled analog input voltage and a reference voltage;
- subtracting means for subtracting an offset voltage of said first sampling means;
- second sampling means for sampling an output voltage of said amplifying means and providing an output voltage;
- logical-level amplifier means for amplifying the output voltage of said second sampling means to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein said output voltage of said second sampling means serves as a comparison signal for execution of the analog-to-digital conversion.
5 more elements
An ADC comprising;
- first sampling means for sampling an analog input voltage by the use of a holding capacitor and by the use of an amplifier whose input and output terminals are short circuited for producing a bias voltage;
- amplifying means for amplifying the voltage difference between a sampled analog input voltage and a reference voltage;
- second sampling means for sampling an output voltage of said amplifying means and providing an output voltage;
- logical-level amplifier means for amplifying the output voltage of said second sampling means to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein said output voltage of said second sampling means serves as a comparison signal for execution of the analog-to-digital conversion.
4 more elements
An ADC comprising;
- first sampling means for sampling an analog input voltage by the use of a first holding capacitor and by the use of a first amplifier whose input and output terminals are short circuited for producing a bias voltage;
- first amplifying means for amplifying the voltage difference between a sampled analog input voltage and a reference voltage;
- second sampling means for sampling an output voltage of said first amplifying means by the use of a second holding capacitor and by the use of a second amplifier whose input and output terminals are short circuited for producing a bias voltage;
- and second amplifying for amplifying the voltage difference between a sampled output voltage of said first amplifying means and a bias voltage produced by said first amplifying means and providing an output voltage;
- logical-level amplifier means for amplifying the output voltage of said second amplifying means to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein said output voltage of said second sampling means serves as a comparison signal for execution of the analog-to-digital conversion.
5 more elements
An ADC comprising;
- first sampling means for sampling an analog input voltage to output the voltage difference between a sampled analog input voltage and a first reference voltage;
- second sampling means for sampling said analog input voltage to output the voltage difference between a sampled analog input voltage and a second reference voltage;
- first amplifying means for amplifying an output voltage of said first sampling circuit;
- second amplifying means for amplifying an output voltage of said second sampling circuit;
- third amplifying means for amplifying the intermediate voltage of said first and second sampling means and providing an output voltage;
- logical-level amplifier means for amplifying the output voltage of said third amplifying means to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein output voltages of said first, second, and third amplifying means serve as comparison voltages for execution of the analog-to-digital conversion.
6 more elements
An ADC comprising;
- first sampling means for sampling an analog input voltage to output the voltage difference between a sampled analog input voltage and a first reference voltage;
- second sampling means for sampling said analog input voltage to output the voltage difference between a sampled analog input voltage and a second reference voltage;
- third sampling means for sampling an output voltage of said first sampling circuit;
- fourth sampling means for sampling an output voltage of said second sampling circuit;
- fifth sampling means for sampling the intermediate voltage between output voltages of said first and second sampling means and providing an output voltage;
- logical-level amplifier means for amplifying the output voltage of said third amplifying means to a logical-level voltage;
- and
- a logic device for converting said logical-level voltage into a digital value;
- wherein output voltages of said third, fourth, and fifth sampling means serve as comparison voltages for execution of the analog-to-digital conversion.
6 more elements
Dependencies are inferred from the claim text.