Patent ID: 7423558

Claim:
A digital/analog conversion circuit, comprising: a plurality of capacitors having electrostatic capacitances substantially equal to each other; a voltage application section configured to apply a first voltage or a second voltage to each of said capacitors; a connection section configured to select a capacitor pair from among said capacitors and connect the selected capacitors in parallel; and a control section configured to control said voltage application section and said connection section in accordance with a predetermined operation sequence including a voltage application operation of applying the first voltage or the second voltage to one of said capacitors in response to the value of a Kth digit of a binary code of a bit length L, L being an integer equal to or greater than three, K being an integer within a range from one to L wherein the first digit is the least significant bit of the binary code, a charge sharing operation of connecting two ones of said capacitors including the one capacitor in parallel to share the charge accumulated in the one capacitor to the two capacitors, a charge retaining operation of disconnecting the two capacitors connected in parallel from each other and retaining the charge accumulated in the other one of the two capacitors, and an initialization operation of initializing the voltage of the one capacitor to the second voltage; said control section being operable to perform the charge sharing operation by (L−K+N) times for the charge supplied from said voltage application section by the voltage application operation for the Kth digit of the binary code, N being an integer equal to or greater than two, and to collect the charge supplied from said voltage application section by the voltage application operations for the digits of the binary code into a common one of said capacitors before the last charge sharing operation of the operation sequence; said control section setting, for at least M higher order ones of the digits of the binary code, the number of times by which the one capacitor takes part in the charge sharing operation within a series of operations before the charge supplied from said voltage application section by the voltage application operation is shared by the last charge sharing operation to twice the number of times by which the one capacitor takes part in the voltage application operation or the charge retaining operation, M being an integer equal to or greater than two.