| 摘要 |
PURPOSE:To decrease the settling time and to attain high speed operation by supplying an inverting current output of a current output circuit to a differentiation circuit, inverting the polarity of the output of differentiation circuit and adding the result to an output current of the current output circuit. CONSTITUTION:The output of the current output circuit 14 is fed to an adder circuit 21 and also the differentiation circuit 24. The output of the differentiation circuit 24 is fed to the adder circuit 21, whose output is fed to a current voltage conversion circuit 12. When input digital signals D1-Dn are changed and an output of the current output circuit 14 changes stepwise, a pulse B is obtained from the differentiation circuit 24 at the point of time of change. The pulse B is added to the output of the current output circuit 14 by the adder circuit 21 in a way of the addition in its changing direction. Then the addition output C is fed to the current voltage conversion circuit 12, its output D is changed in response to the output change of the current output circuit 14. When the output of the current output circuit 14 changes stepwise in this way, since a differentiation pulse increasing the change is superimposed on the output of the current output circuit 14, the settling time of the current voltage conversion circuit is reduced and the DA converter with higher speed is obtained by the reduction.
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