Digital-to-analog converter of the current-adding type

A digital-to-analog converter of the current-adding kind for converting an n-bit digital signal to an analog signal, comprising:

• first circuit means receiving in parallel the bits of said digital signal and producing two outputs having respective voltage levels based on the numerical value of said n-bit digital signal;
• second circuit means receiving said two outputs from said first circuit means and including a resistance network for producing a plurality of divided voltages from said outputs at nodes of said network of said second circuit means;
• a plurality of comparator means having inputs connected to said nodes of said second circuit means for producing current level signals based upon comparisons of voltages at selected nodes;
• and
• current adding means connected to said current level signals for producing a summed voltage having level corresponding to the numerical value of said n-bit digital input signal.

Apparatus for converting n-bit digital signals to corresponding analog voltage levels, comprising:

• input circuit means connected to receive in parallel the bits of said n-bit digital signals and for producing buffered output signals therefrom;
• first voltage divider means having said buffered output signals connected to a first plurality of voltage dividing nodes formed therein for producing signals having respective voltage levels corresponding to the numerical values of said n-bit digital signals;
• second voltage divider means receiving said signals from said first voltage divider and having a second plurality of voltage dividing nodes;
• comparator means having a plurality of inputs connected to said second plurality of voltage dividing nodes of said second voltage divider means for comparing selected pairs of voltages present at said second plurality of voltage dividing nodes and producing an output current upon each successful comparison;
• and
• current adding means, connected to add all said output currents from said comparators to form said analog signal thereacross.