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

摘要

The dynamic range of operation of a digital-to-analog converter of an audio system, including 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 said subsets first and second in function of the value of each sampled code of a pulse code modulated input signal, is embedded by multiplying by a certain factor incoming digital codes of said pulse code modulated input signal after their value has remained lower than a predefined threshold value for a certain period of time and for as long as their value equals or surpasses than said threshold value and correspondingly scaling and de-scaling by the same factor the amplitude of said analog output current contributions produced by the elementary current sources of said two subsets.