Patent ID: 6888481

Claim:
A D/A converting device with an offset compensation function for compensating a DC offset of a D/A converter, comprising: a comparator for detecting the DC offset of the D/A converter; a changing switch for selecting a first input mode in which first and second signals, wherein at least one of these signals is an output signal of the D/A converter, are input into first and second input terminals of the comparator respectively, and a second input mode in which the second and first signals are input into the first and second terminals of the comparator respectively; and input data correcting means for calculating a third compensation value from a first compensation value which is obtained based on an output signal of the comparator in the first input mode and a second compensation value which is obtained based on an output signal of the comparator in the second input mode, and also correcting input data of the D/A converter by using the third compensation value, wherein the input data correcting means determines the first and second compensation values by using a successive approximation method, wherein the input data correcting means determines the first and second compensation values by using the successive approximation method based on a binary search, and wherein the input data correcting means adds Â½ to the first and second compensation values when least significant bits of the first and second compensation values are 0, and subtracts Â½ from the first and second compensation values when the least significant bits of the first and second compensation values are 1.