High dynamic linearity current-mode digital-to-analog converter architecture
First Claim
1. A segmented, current-mode Digital-to-Analog Converter (DAC) comprising:
- a summing node;
a dump node;
a control input;
a Most Significant Bit (MSB) current leg coupled to the summing node, the MSB current leg conducting a first current relative to the summing node in response to the control input; and
a Least Significant Bit (LSB) current leg coupled to the summing node, the LSB current leg conducting a second current relative to the summing node in response to the control input and conducting current relative to the dump node.
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Abstract
The present invention dramatically reduces dynamic mismatches between the different current segments of a segmented current-mode DAC. By providing substantially the same local architecture for each of the individual current segments, parasitic effects of any physical realization can be controlled. In one embodiment, the most-significant-bit (MSB) current segments and the least-significant-bit (LSB) current segments each have the same number of multiple internal current branches. In the MSB segments, the multiple internal current branches are combined at a source node; whereas, in the LSB segment, a portion of the segment current is dumped, or wasted, through at least some of the internal current branches.
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Citations
35 Claims
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1. A segmented, current-mode Digital-to-Analog Converter (DAC) comprising:
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a summing node;
a dump node;
a control input;
a Most Significant Bit (MSB) current leg coupled to the summing node, the MSB current leg conducting a first current relative to the summing node in response to the control input; and
a Least Significant Bit (LSB) current leg coupled to the summing node, the LSB current leg conducting a second current relative to the summing node in response to the control input and conducting current relative to the dump node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A digital-to-analog converting method for generating a linear, high-speed analog output signal comprising:
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receiving a control input;
conducting in a Most Significant Bit (MSB) current leg, a first current relative to a summing node in response to receiving the control input;
conducting in a Least Significant Bit (LSB) current leg, a second current relative to the summing node in response to receiving the control input; and
conducting in the LSB current leg, a current relative to a dump node. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A digital-to-analog converter comprising:
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means for receiving a control input;
means for conducting, in response to the received control input, a first current in a Most Significant Bit (MSB) current leg;
means for conducting, in response to the received control input, a second current in a Least Significant Bit (LSB) current leg; and
means for dumping a portion of the second current; and
means for combining the first current, the second current, and the dump current.
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Specification