Digital-to-analog converter having overlapping segments

A method for converting a multi-bit digital word into a corresponding analog value, the method comprising:

• dividing the multi-bit digital word into a lower digital word portion and an upper digital word portion;
• making the binary weight of the most significant bit (msb) of the lower word portion the same as the binary weight of the least significant bit (lsb) of the upper word portion;
• detecting whether the lsb of the upper word portion changes state;
• decoding the multi-bit digital word by responsively inverting the msb of the lower word portion each time the lsb of the upper word portion changes state;
• translating the lower word portion and upper word portion of the decoded multi-bit digital word into respective intermediate analog values;
• and
• summing the respective intermediate analog values together to provide an analog output corresponding to the value of the decoded multi-bit digital word.

A digital-to-analog converter (DAC) for translating a sequence of multi-bit digital words into corresponding analog values, the sequence including a current digital word and a new digital word, wherein the DAC comprises:

• circuit means for providing the sequence of digital words, each digital word having a digital value and having multi-bit word portions n.sub.1 and n.sub.2, in which portion n.sub.1 is a least significant portion and portion n.sub.2 is a most significant portion, and in which the weight of the most significant bit (msb) of word portion n.sub.1 is the same as the weight of the least significant bit (lsb) of word portion A.sub.2 ;
• a first exclusive-OR gate having a first input receiving the lb of word portion n.sub.2 of the current digital word, a second input receiving the lb of word portion n.sub.2 of the new digital word, and an output;
• a second exclusive-OR gate having a first input coupled to the output of the first exclusive-OR gate, a second input receiving the msb of word portion n.sub.1 of the new digital word, and an output providing a mapped value for the msb of word portion n.sub.1 of the new digital word;
• and
• circuit means for translating word portions n.sub.1 and n.sub.2 of the new digital word, with the mapped value of the msb of word portion n.sub.1, into respective analog values and for summing the respective analog values together to provide an analog output indicative of the digital value of the digital word.