Patent ID: 7236152

Claim:
A digital/analog conversion device outputting an analog voltage according to digital data of a plurality of weighted bits, comprising: a pulse number control circuit supplying, to a first node, pulses of a number according to said digital data, said pulses including a first transition edge changing from an initial level to a predetermined level and a second transition edge returning from said predetermined level to said initial level; and a charge pump circuit changing, in a stepwise manner, each time one of said pulses is supplied to said first node, a voltage on an output node having an output capacitor connected thereto, said charge pump circuit including a pump capacitor connected between a second node and said first node, a switch element connected between said second node and said output node to be turned on at a timing at which said first transition edge of each of said pulses is transmitted to said first node and turned off at a timing at which said second transition edge thereof is transmitted to said first node and a bias circuit changing, according to the change of the voltage on said output node, a voltage on said second node with the same polarity as that of the change of the voltage on said output node.