Patent ID: 8125361

Claim:
A digital-to-analog converter (DAC) calibration system comprising: a multiplexer receiving a digital input sequence and outputting a first digital signal and a plurality of second digital signals, wherein the first digital signal is orthogonal to the second digital signals; a first current source switch (CSS) element having: a first current source configured to generate a first output current having a first output current magnitude controlled by a bias voltage applied to the first current source; a first current switch configured to receive the first digital signal and convert the first output current received from the first current source to a first output current pulse based on the first digital signal; and a first weighting network configured to scale the first output current pulse based on a predetermined first weighting factor; a plurality of second current source switch (CSS) elements each having: a second current source configured to generate a second output current controlled by the bias voltage applied to the second current source; a second current switch configured to receive the respective second digital signal and convert the second output current received from the second current source to a second output current pulse based on the respective second digital signal; and a second weighting network configured to scale the second output current pulse based on a predetermined second weighting factor; an output node coupled to the first weighting network and the second weighting networks, receiving the first output current pulse and the second current pulses, the combination of which forms a total output current pulse; a resistive element coupled between the output node and a ground source, conducting the total output current pulse to the ground source to produce an output voltage on the output node; a first calibration module configured to receive the first digital input and convert the output voltage to a target voltage having an average output voltage value that reflects the first output current magnitude; an average measurement module coupled to the first calibration module and configured to measure the average output voltage value; and a second calibration module coupled to the average measurement module and configured to compare the average output voltage value with a predefined voltage value and adjust the bias voltage to control the first current source and the second current sources.