Patent ID: 6281824
Filing Date: 2001-08-28
Classification: H03K,H03M

Abstract:
A D/A converter comprising:2.sup.N (here, N=2, 3, - - - ) constant electric current sources having addresses and having respective constant electric current values equal to each other;switching means for outputting constant electric currents from selected constant electric current sources selected from the 2.sup.N constant electric current sources;electric current adding means for adding the constant electric currents from said selected constant electric current sources outputted from the switching means; andswitching signal generating means having N-bit adding means supplied with input data Di and delay means for delaying an adding output of the N-bit adding means by one sample period and for supplying a delayed adding output to the N-bit adding means and adding the delayed adding output to said input data Di, for generating a switching signal to control said switching means such that a final address of a switching signal previously delayed by one sample from the delay means is detected and, on the basis of the present sample data and a detected final address of the switching signal previously delayed by one sample, respective constant electric currents are outputted from Di ones of the 2.sup.N constant electric current sources selected in accordance with input data DI {here, Di=0, 1, 2, 3, - - - (2.sup.N -1)} having N-bits in input word length so as to use the 2.sup.N constant electric current sources one by one in accordance with an order of said addresses until a sum of values of one of the input data or a continuous plurality of the input data among said 2.sup.N constant electric current sources exceeds 2.sup.N, and then to again use said 2.sup.N constant electric current sources one by one in accordance with an order to said addresses every time a sum of values of said one input data or said continuous plurality of the input data exceeds 2.sup.N.