It is low in offset voltage of the operation amplifier the switched condenser of sensitivity, 1 bits digital/the analog converter

摘要

(57) Abstract The switched condenser DAC system, the entry lead line (62 and 64) with, the output lead line (66 and 68) with, the integrating capacitor which is jointed with the entry lead line and the output lead line (C3 and C4) with the operation amplifier which it possesses (60) has the integrating circuit which is included. The sampling switch (78), in at least one of 1st and 2nd non overwraped time interval in order the entry condenser which is charged input potential (V _ref) by (C1 and C2) to joint, it is operation possible, 1st time interval detail is split to 1st and 2nd non overwraped sub interval, 2nd time interval detail is split to 3rd and 4th non overwraped sub interval. The transfer switch (80), in order electric charge the integrating capacitor (C3 and C4) to transfer from the entry condenser, in at least one of 1st and 3rd sub interval, in order to joint the entry condenser to transfer electric charge from the entry condenser, it is operation possible. The discharge switch (S8 and S10), in order to joint the entry condenser to the discharge node in at least one of 2nd and 4th sub interval, it is operation possible. In one example where this invention is desirable, the sampling switch joints the entry condenser in one of 1st and 2nd sub interval, the transfer switch joints the entry condenser in one of 1st and 3rd sub interval, the discharge switch joints the entry condenser in one of 2nd and 4th sub interval.