US 11,923,866 B2
Digital-to-analog conversion apparatus and method having signal calibration mechanism
Hsuan-Ting Ho, Hsinchu (TW); Shih-Hsiung Huang, Hsinchu (TW); and Liang-Wei Huang, Hsinchu (TW)
Assigned to REALTEK SEMICONDUCTOR CORPORATION, Hsinchu (TW)
Filed by REALTEK SEMICONDUCTOR CORPORATION, Hsinchu (TW)
Filed on Mar. 1, 2022, as Appl. No. 17/683,397.
Claims priority of application No. 110114807 (TW), filed on Apr. 23, 2021.
Prior Publication US 2022/0345139 A1, Oct. 27, 2022
Int. Cl. H03M 1/10 (2006.01)
CPC H03M 1/1014 (2013.01) 12 Claims
OG exemplary drawing
 
1. A digital-to-analog conversion (DAC) apparatus having signal calibration mechanism, comprising:
a DAC circuit comprising a plurality of current sources each having a current offset, and configured to control an operation state of each of the current sources to be one of a first current output state and a second current output state according to an input digital codeword comprised by an input digital signal, so as to generate an output analog signal according to a total current of the current sources, wherein each of the current sources outputs a current with a same current amount but opposite signs respectively under the first current output state and the second current output state;
an echo transmission circuit to process the output analog signal to generate an echo signal;
a calibration circuit to receive the input digital signal and perform mapping from a codeword offset mapping table according to the input digital codeword to generate an offset, wherein the codeword offset mapping table comprises a one-to-one correspondence relation between a plurality of codewords and a plurality of codeword offsets;
an echo-canceling circuit to process the offset according to a group of echo-canceling coefficients to generate an echo-canceling signal; and
a calibration parameter calculating circuit configured to:
generate an offset amount according to a difference between the echo signal and the echo-canceling signal;
categorize the offset amount corresponding to the different input digital codeword into a plurality of groups according to the operation state of each of the current sources to perform statistic operation;
set each of the current sources as a target current source to perform calculation among the groups such that the current offset of each of the current sources besides the target current source cancels out to calculate the current offset of the target current source; and
convert the current offset of the current sources to the codeword offsets to update the codeword offsets in the codeword offset mapping table.