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US 6,388,593 B2Granted
Differential non-linearity correction scheme
AssigneePhotobit Corporation
InventorEric R. Fossum
Life of this patent
Estimating the term…
Abstract
Differential non-linearity errors in an A/D converter are corrected by an analog system. The system produces different analog voltages which are used to correct the input voltage to the capacitor. The input voltage is changed by an amount which is effective to correct the CΔV to be the same as it would have been if the DNL error had not occurred.
Claims17
A compensated analog-to-digital converter system, comprising:
- an analog-to-digital converter module, of a type which relies on scaled capacitors to determine an output value;
- an array of scaled capacitors including first, second and third capacitors, a common line connected commonly to one end of each of the capacitors, a plurality of switched connections, each connected to a second end of each of the capacitors, and switching the second end of said each capacitors between a first potential and a second potential which is different than the first potential, and
- a voltage source producing a first voltage for said first potential of said first capacitor, and producing a second voltage for said first potential of a second capacitor, said second voltage being different than said first voltage and producing a third voltage for said first potential of a third capacitor, said third voltage being different than said first and second voltages.
A system, comprising:
- an analog-to-digital converter module, of a type which relies on capacitors which have different values to determine an output digital value, said analog to digital converter module including a plurality of capacitors, with at least one capacitor for each of a plurality of bits, each of said at least one capacitors having a different capacitive value;
- and
- a plurality of correction elements, respectively connected to at least a plurality of said capacitors, and providing correction values which compensate for inaccuracies in said different capacitive values, each of said correction elements producing a different output voltage, each of which is coupled to a respective capacitor, and used to correct for said inaccuracies in said capacitors.
A system, comprising:
- an analog-to-Digital converter module, of a type which relies on capacitors which have different values to determine an output digital value, said analog to digital converter module including a plurality of capacitors, with at least one capacitor for each of a plurality of bits, each of said at least one capacitors having at different capacitive value;
- and
- a plurality of correction elements, respectively connected to at least a plurality of said capacitors, and each formed of a digital to analog converter, receiving said digital control value which is related to a correction for inaccuracies in said capacitive values, and each of said digital to analog converters producing an analog output voltage, connected to the respective capacitor, and used to correct for said inaccuracies.
Dependencies are inferred from the claim text.