Digital-to-analog converting circuit and digital-to-analog converting method

1. A digital-to-analog converting circuit comprising:

m×N (m is an integer equal to or more than two and N is an integer equal to or more than two) or more number of digital-to-analog converting elements converting an input digital code of N+1 values to an analog code in one of three states of H level, L level, and non-selection to output;

a first selecting section selecting digital-to-analog converting elements that output r (r is an integer equal to or smaller than N) number of H levels for a thermometer digital code expressing the input digital code with the number of H levels and L levels; and

a second selecting section selecting the digital-to-analog converting elements that output N−r number of L levels,

wherein selecting of the digital-to-analog converting element is controlled so that the same digital-to-analog converting element does not continuously output the same analog code as the first and second selecting sections cause the digital-to-analog converting elements selected respectively at the first digital-to-analog converting timing and at the second digital-to-analog converting timing to circulate in an inverse direction to each other.

2. A digital-to-analog converting circuit comprising:

a first digital-to-analog converting element set having 2N (N is an integer equal to or more than two) or more number of digital-to-analog converting elements converting an input digital code of N+1 values to an analog code in one of two states of H level and non-selection to output;

a second digital-to-analog converting element set having 2N or more number of digital-to-analog converting elements converting an input digital code to an analog code in one of two states of L level and non-selection to output;

a first selecting section selecting, from the first digital-to-analog converting element set, digital-to-analog converting elements that output r (r is an integer equal to or smaller than N) number of H levels with respect to a thermometer digital code expressing the input digital code with the number of H levels and L levels; and

a second selecting section selecting, from the second digital-to-analog converting element set, the digital-to-analog converting elements that output N−r number of L levels,

wherein selecting of the digital-to-analog converting element is controlled so that the same digital-to-analog converting element is not continuously selected as the first and second selecting sections cause the digital-to-analog converting elements selected respectively at the first digital-to-analog converting timing and at the second digital-to-analog converting timing to circulate.

3. A digital-to-analog converting circuit comprising:

2N or more number of digital-to-analog converting elements converting an input digital code of N+1 (N is an integer equal to or more than two) values to an analog code to output;

a selecting section selecting N-number of digital-to-analog converting elements; and

a control section controlling a second selecting so that each of the at least N-number of digital-to-analog converting elements used for digital-to-analog converting does not continuously output the same analog code at a second digital-to-analog converting timing following a first selecting by the selecting section of the N-number of digital-to-analog converting elements at a first digital-to-analog converting timing,

wherein the 2N or more number of digital-to-analog converting elements are formed with M (M is an integer equal to or more than three) digital-to-analog converting element sets having N-number of digital-to-analog converting elements respectively.

4. The digital-to-analog converting circuit according to claim 3 ,

wherein the control section selects one set from the M sets at each digital-to-analog converting timing so that such a frequency that a digital code of an H level is inputted and such a frequency that a digital code of an L level is inputted are same at every digital-to-analog converting element in the digital-to-analog converting element sets which have not been used at a previous digital-to-analog converting timing.

5. The digital-to-analog converting circuit according to claim 4 ,

wherein the selecting section selects the N-number of digital-to-analog converting elements in each digital-to-analog converting element set respectively in order to circulate the digital-to-analog converting elements converting the digital code of the H level and the L level in an inverse direction to each other.