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US 8,134,486 B2Granted
DAC calibration
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsFang-Shi Jordan Lai, Yung-Fu Lin, Kuo-Ming Wang, Hsu-Feng Hsueh, Cheng Yen Weng
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Abstract
Mechanisms to calibrate a digital to analog converter (DAC) of an SDM (sigma delta modulator) are disclosed. An extra DAC element in addition to the DAC is used to function in place of a DAC element under calibration. A signal (e.g., a random sequence of −1 and +1) is injected to the DAC element under calibration, and the estimated error and compensation are acquired.
Claims21
A method comprising:
- using 2M DAC elements for an M-bit digital-to-analog converter;
- selecting a first one of the 2M DAC elements as a calibration DAC element;
- replacing a second one of the 2M DAC elements to be calibrated with the calibration DAC element so that the remaining 2M−2 DAC elements and the calibration DAC element constitute 2M−1 DAC elements to function in the digital-to-analog converter;
- injecting a signal to the DAC element to be calibrated;
- and
- estimating a DAC error for the DAC element to be calibrated.
3 more elements
A method comprising:
- using a plurality of DAC elements;
- selecting a first one of the plurality of DAC elements as a calibration DAC element;
- selecting a second one of the plurality of DAC elements as a DAC element under calibration;
- replacing a thermometer code of the calibration DAC element with a thermometer code of the DAC element under calibration;
- injecting a signal to the DAC element under calibration;
- and
- using the signal injected to the DAC element under calibration and output of a sigma delta modulator to estimate an error for the DAC element under calibration.
4 more elements
A method comprising:
- using a plurality of DAC elements for a digital-to-analog converter used in a sigma delta modulator;
- selecting a DAC element as a DAC element under calibration;
- injecting a random-sequence signal to the DAC element under calibration;
- and
- using the random-sequence signal injected to the DAC element under calibration and output of the sigma delta modulator to estimate error for the DAC element under calibration.
2 more elements
Dependencies are inferred from the claim text.