| 摘要 |
PURPOSE:To make a A/D converter more high-accurate and to simplify constitution of the A/D converter by adding a subtraction circuit to the A/D converter. CONSTITUTION:Plural subtraction circuits 11, 12-1m are provided to a basic i-bit A/D converter 22 and analog voltages V1, V2-Vm are inputted to the input terminals of respective subtraction circuits 11, 12-1m, thereby subtracting the reference voltage VR. When subtraction cannot be performed by respective subtraction circuit 11, 12-1m, the most significant n bit OBn-OB1 of digital conversion output of input analog voltage V1 are outputted from a decoder. In addition, output Vm+1 of the last subtraction circuit 1n is added to a converter 22. Reference voltage VR is added to the converter 22, and the voltage VR is converted as full scale voltage to 1-bit digital data, thereby outputting from an output buffer 24. Thus, the A/D converter is made more accurate and the A/D converter 22 is simplified. |
