Dynamic current mismatch accumulation schemes for digital-to-analog converters
AssigneeQUALCOMM Incorporated
InventorsSarthak Kalani, Andrew Weil, John Abcarius
Life of this patent
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Abstract
Techniques and apparatus for determining dynamic current mismatches in a current-steering digital-to-analog converter (DAC) are provided. One example technique generally includes accumulating current mismatches between a DAC cell of a plurality of DAC cells and a reference cell using a capacitive element and changing a polarity of the capacitive element during the accumulating. The timing of the accumulating may be controlled such that a static current mismatch between the DAC cell and the reference cell is at least reduced and a dynamic current mismatch between the DAC cell and the reference cell is enhanced.
Claims20
A digital-to-analog converter (DAC) circuit comprising:
- a plurality of DAC cells, each DAC cell comprising a current source, a first switch coupled between the current source and a DAC output node, and a second switch coupled between the current source and a complementary DAC output node;
- a reference cell comprising a reference current source, a third switch coupled between the reference current source and the complementary DAC output node, and a fourth switch coupled between the reference current source and the DAC output node;
- a capacitive element;
- an integrator comprising a first input coupled to a first terminal of the capacitive element and a second input coupled to a second terminal of the capacitive element;
- a first set of switches configured to selectively couple the first terminal of the capacitive element to the DAC output node and the second terminal of the capacitive element to the complementary DAC output node;
- and
- a second set of switches configured to selectively couple the second terminal of the capacitive element to the DAC output node and the first terminal of the capacitive element to the complementary DAC output node.
A method of digital-to-analog converter (DAC) calibration, comprising:
- accumulating current mismatches between a DAC cell of a plurality of DAC cells and a reference cell using a capacitive element;
- and
- changing a polarity of the capacitive element during the accumulating.
Dependencies are inferred from the claim text.