Switched capacitor type digital-analog converter which generates an analog driving signal from a digital signal by activation of a capacitor

摘要

A switched capacitor type digital-analog converter is provided with an input capacitor group, a first switch group (3-1 to 3-n) a second switch group, a reference voltage switch (6) , a comparator (9), an output capacitor (2) and a short-circuit switch (7). The input capacitor group is composed of an input capacitor (1-0) and a plurality of shared input capacitors (1-1 to 1-n). The first switch group (3-1 to 3-n) applies a first voltage (V1) to the plurality of shared input capacitors (1-1 to 1-n). The second switch group applies a second voltage (V2) to the input capacitor group. The reference voltage switch (6) applies a reference voltage (Vr) to the input capacitor group. The comparator (9) compares an output of the input capacitor group with the reference voltage. An input of the output capacitor (2) is connected to an output of the input capacitor group, and an output thereof is connected to an output of the comparator (9). The short-circuit switch (7) is coupled to the output capacitor (2) in parallel. A capacitance of the output capacitor (2) is smaller than a synthesis capacitance of the input capacitor group (a total value of capacitances of the respective capacitors within the input capacitor group).