Patent ID: 7397407

Claim:
A D/A conversion circuit for use with low-potential and high-potential power supplies, the D/A conversion circuit comprising: a resistor string including a plurality of resistor elements coupled in series between the low-potential power supply and the high-potential power supply; a plurality of first switch groups, coupled among the resistor elements, for selectively outputting any divided voltages generated among the resistor elements in accordance with a digital signal, the first switch groups each having a common output coupled to a corresponding one of a plurality of nodes; a second switch group, coupled between the plurality of nodes and an output terminal of the D/A conversion circuit, for selectively coupling one of the nodes to the output terminal to output the divided voltage; and a third switch group, each switch of the third switch group being coupled in parallel with a predetermined switch in a corresponding one of the first switch groups, wherein when a switch of the second switch group is turned off, switches of the first switch group that are coupled to the turned-off switch of the second switch group via a corresponding one of the nodes is turned off, and a switch of the third switch group that is coupled to the turned-off switch of the second switch group is turned on to apply a predetermined voltage to the corresponding one of the nodes.