Enhancement of the dynamic range of a multibit digital-to-analog converter

摘要

A digital-to-analog converter (DAC) for an audio system may include at least first and second subsets of individually selectable elementary current sources for delivering analog output current contributions, a code conversion circuit for selecting elementary current sources of first and second subsets as a function of codes of a pulse code modulated (PCM) input signal. The DAC may multiply by a certain factor incoming codes of the PCM signal after their value has remained lower than a threshold for a certain period of time and for as long as their value equals or surpasses the threshold value, and may correspondingly scale and de-scale by the same factor the amplitude of the analog output current contributions produced by the elementary current sources of the two subsets.