Variable potential generating circuit using current-scaling adding type D/A converter circuit in semiconductor memory device

摘要

A variable potential generating circuit includes a resistive potential divider circuit and first and second operational amplifiers. The resistive potential divider circuit includes a switching element and a current-scaling type digital/analog converter circuit connected in series between a power supply node and a ground node. The resistive potential divider circuit has a first node at which a divided potential obtained by resistive division of a variable potential to be output from a variable potential output node appears and a second node to which a virtual potential is applied. The first operational amplifier compares the divided potential of the first node with a reference potential to effect the feedback control for setting the variable output potential equal to the reference potential. The second operational amplifier compares the virtual potential of the second node with the reference potential to effect the feedback control for setting the virtual potential equal to the reference potential.