Patent ID: 8907832

Claim:
A secondary voltage divider of a dual-string digital-to-analog converter (DAC) comprising: a secondary resistor string comprising a plurality of secondary resistors, the secondary resistor string comprising a plurality of secondary resistor nodes, the secondary resistor string configured to divide a selected primary DAC output voltage applied as a secondary DAC input voltage across the secondary resistor string into a plurality of divided voltage levels across the plurality of secondary resistors; a secondary switch unit comprising a plurality of secondary switches each coupled to a respective secondary resistor node among the plurality of secondary resistor nodes, each secondary switch among the plurality of secondary switches configured to select a current secondary resistor node among the plurality of secondary resistor nodes of the secondary resistor string to provide a divided secondary voltage level across the current selected secondary resistor node to be applied to a DAC output voltage node of the dual-string DAC; and a switch logic unit configured to: receive a secondary DAC input code and a polarity indicator indicating a polarity of the secondary DAC input voltage; and select a current secondary switch among the plurality of secondary switches based on the polarity indicator and the secondary DAC input code to select a secondary resistor node coupled to a current selected secondary switch, to cause the divided secondary voltage level across the current selected secondary resistor node to be applied to the DAC output voltage node of the dual-string DAC.