Patent ID: 7646322

Claim:
A folded R-2R ladder current-steering digital-to-analog conversion circuit, comprising: an end current-steering circuit, comprising a first electrical contact; a first two-ended circuit element; a second electrical contact, wherein the two ends of the first two-ended circuit element are electrically coupled between the first contact and the second contact, the resistance of the first two-ended circuit element between the first contact and the second contact being a first resistance value; and a plurality of current sources, each current source having a switching element electrically coupled to the second contact, wherein the switching element controls the current flowing through the current source by turning on, and controls the current not flowing through the current source by turning off; a plurality of sequentially arranged R-2R current-steering circuits, each comprising: a first contact, all first contacts are electrically coupled together; a first two-ended circuit element; a second contact; a second two-ended circuit element; a third contact, wherein the two ends of the second two-ended circuit element are electrically coupled between the second contact and the third contact, the resistance of the second two-ended circuit element between the second contact and the third contact being a second resistance value, wherein, in each of the R-2R current-steering circuits, the first resistance value is two times the second resistance value, and the first resistance value in the R-2R current-steering circuit being two times the first resistance value in the end current-steering circuit; and a plurality of current sources, wherein prior to arranging with the end current-steering circuit, the plurality of sequentially arranged R-2R current-steering circuits form a sequential R-2R circuit network, wherein the third contact of each current-steering circuit electrically couples to the second contact of the following current-steering circuit.