Digital-to-analog converter with correction for parasitic routing resistance

Abstract

An embodiment of a digital-to-analog converter circuit includes a resistor network connected to an output node, a switch network having a first plurality of switches connecting the resistor network to a first circuit node and a second plurality of switches connecting the resistor network to a second circuit node, a voltage reference to supply a reference voltage to the first circuit node, and a current generator connected to the first circuit node and the second circuit node, to generate a compensation current, draw the compensation current from the first circuit node, and supply the compensation current to the second circuit node. The current generator can generate the compensation current as a function of a current or a voltage of a component of the voltage reference or as a function of an analog output voltage produced at the output node.

Description

BACKGROUND INFORMATION[0001]Many types of digital-to-analog converter (DAC) circuits include a resistor network having individual resistors connected by a switch network to either a reference voltage or ground as a function of individual bits of a digital input. An analog output voltage produced on a node of the resistor network typically represents a conversion of the digital input to the analog domain.[0002]Certain problems arise with the use of such resistor and switch networks in DAC circuits, however. Connections of the resistor network by the switch network to the reference voltage or ground depend on the value of the digital input at any given time, and therefore conductor lines supplying the reference voltage and ground experience a variable current draw. Additionally, the resistor and switch networks typically include a relatively large number of resistors and switches connected to these conductor lines, with these connections distributed over a physical dimension of the co...

AI Technical Summary

Benefits of technology

The patent text describes a problem in DAC circuits where the connection of the resistor and switch networks to the reference voltage or ground can result in variable current draw and parasitic resistances in the conductor lines, leading to degraded linearity and reduced accuracy of the DAC circuit. The patent proposes a solution in the form of a current generator that generates a compensation current to reduce the impact of these issues. The current generator can be connected to the reference voltage or ground as a function of the digital input to improve linearity and accuracy. The technical effect of this solution is improved linearity and reduced nonlinearity in DAC circuits, resulting in better performance and accuracy.

Problems solved by technology

Certain problems arise with the use of such resistor and switch networks in DAC circuits, however.

Additionally, the resistor and switch networks typically include a relatively large number of resistors and switches connected to these conductor lines, with these connections distributed over a physical dimension of the conductor line, resulting in parasitic resistances existing in the conductor line between the connections.

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