| 摘要 |
PURPOSE:To improve monotonousness and precision of integral characteristics by converting n-bit digital data into 2<n-1> data and then by extracting an analog signal by switching the switch of a fine current source that corresponds to the converted data. CONSTITUTION:Of sixteen bits of input digital data, bit MSB11 is input to decoder 1, and the remaining five low-order bits including LSB are distributed to resistance ladder circuit 2 for processing. The output of decoder 1 is supplied to matrix circuit 3 in which 2,048 intersection selecting elements 4 consisting of switch S and fine current source DELTAI are arrayed in a matrix equivalent to eleven bits and intersection selecting element 4 is selected to exercise selective control over the fine current source. In this case, the control is exercised so that when the n-th switch S is turned on, the preceding switches S are also turned on. Further, both the outputs of matrix circuit 3 and ladder circuit 2 are added as the output of D/A converter, securing high precision. |
