Digital-to-analog conversion apparatus having current source measuring mechanism and current source measuring method of the same

A digital-to-analog conversion apparatus having current source measuring mechanism, comprising:

• a digital-to-analog conversion circuit comprising a plurality of thermometer-controlled current sources and configured to in turn set one of the thermometer-controlled current sources as an initial current source to be operated according to two specific input codewords comprised by an input digital signal, so as to generate an output analog signal according to a total current of the thermometer-controlled current sources, wherein the two specific input codewords control a thermometer-controlled operation status of each of the thermometer-controlled current sources to be one of a first current output status and a second current output status, and the two specific input codewords respectively make values of the output analog signal have opposite signs and substantially identical absolute values;
• an echo transmission circuit to process the output analog signal to generate an echo signal;
• an echo-canceling circuit to process the input digital signal according to a group of echo-canceling coefficients to generate an echo-canceling signal and to keep receiving an error signal to make the group of echo-canceling coefficients converge;
• a current calculation circuit to perform statistics on the group of converged echo-canceling coefficients to generate a plurality of converged coefficients statistics values corresponding to a number of the thermometer-controlled current sources and perform calculation on the converged coefficients statistics values and a predetermined inverse matrix to generate a current amount of each of the thermometer-controlled current sources, wherein a predetermined matrix inverse to the predetermined inverse matrix reflects a different status section and an identical status section of each of the thermometer-controlled current sources corresponding to the two specific input codewords when each of the thermometer-controlled current sources is set to be the initial current source;
• and
• an error calculation circuit to subtract the echo-canceling signal from the echo signal to generate the error signal.