Patent ID: 6600436
Filing Date: 2003-07-29
Classification: H03M

Abstract:
A D/A converter circuit for converting n-bit digital signals (n is a natural number) into an analog signal, comprising:capacitances in the number of m (m is a natural number smaller than n) each having first and second electrodes; tone voltage lines in the number of 2nâˆ’m different in voltage value one from another; and first switches in the number of 2nâˆ’m, second switches in the number of m and a third switch, wherein the capacitances in the number of m are charged under control of by higher order (nâˆ’m)-bit digital signals of among the n-bit digital signals in a precharge period; wherein the capacitances in the number of m are charged under control of by lower order m-bit digital signals of among the n-bit digital signals in a write period; wherein the first electrodes possessed by all the capacitances in the number of m are connected to either one of a first power source or a second power source respectively through the second switches in the number of m; wherein the tone voltage lines in the number of 2nâˆ’m are connected to one terminal of the third switch respectively through the first switches in the number of 2nâˆ’m; wherein the other terminal of the third switch are connected to the second electrodes possessed by all the capacitances in the number of m; and wherein voltages on the second electrodes possessed by all the capacitances in the number of m are outputted as an analog signal.