Configurable digital-to-analog converter calibration
AssigneeAnalog Devices International Unlimited Company
InventorsDennis A. Dempsey, Ken Bryan Fulgosino Fabay
Life of this patent
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Abstract
The present disclosure relates to a digital-to-analog converter comprising an impedance network and a transfer function modification circuit. The transfer function modification circuit comprises a DAC and a demultiplexer. The demultiplexer may be used to selectively connect the output of the DAC to different respective nodes of the impedance network, allowing positive or negative currents to be injected into the node and modify the transfer function. By using a demultiplexer to selectively couple to different nodes, the node into which the current is injected may be modified post-manufacture, allowing transfer function modification.
Claims20
A digital-to-analog converter, DAC, comprising:
- an impedance network, comprising a plurality of impedance elements coupled together via a plurality of nodes, wherein the impedance network is configured to be coupled to a reference voltage and to generate a plurality of voltage values at the plurality of nodes;
- and
- a transfer function modification circuit, comprising:
- a trim current DAC, the trim current DAC comprising an input for receiving trim codes and an output;
- and
- a demultiplexer, the demultiplexer comprising an input and a plurality of outputs,
- wherein the output of the trim current DAC is coupled to the input of the demultiplexer,
- wherein each output of the plurality of outputs of the demultiplexer is coupled to a respective node of the plurality of nodes, and
- wherein the trim current DAC is configured to modify the transfer function of the DAC by injecting current into, or draining current from, a selected node of the plurality of nodes via a selected output of the demultiplexer.
A digital-to-analog converter, DAC, comprising:
- an impedance network, comprising a plurality of impedance elements coupled together via a plurality of nodes, wherein the impedance network is configured to be coupled to a reference voltage and to generate a plurality of voltage values at the plurality of nodes;
- and
- a transfer function modification circuit, comprising:
- current injection means, the current injection means configured to be coupled to a subset of the plurality of nodes;
- wherein the current injection means is configured to modify the transfer function of the DAC by selecting a node of the subset of the plurality of nodes and injecting current into, or draining current from, the selected node of the subset of the plurality of nodes.
A method of modifying a transfer function of a digital-to-analog converter (DAC) comprising an impedance network, the impedance network comprising a plurality of resistor elements coupled together via a plurality of nodes, wherein the impedance network is configured to be coupled to a reference voltage and to generate a plurality of voltage values at the plurality of nodes, the method comprising:
- selecting a respective node of the plurality of nodes to inject current into, or drain current from;
- injecting the current into, or draining the current from, the selected node of the impedance network to modify the transfer function of the DAC.
Dependencies are inferred from the claim text.