| 摘要 |
PURPOSE: An analog-to-digital converter suitable for preventing a malfunction and reducing power consumption is provided to prevent an operational error by modifying high-bit data. CONSTITUTION: A partial voltage generation circuit generates a plurality of partial voltages for the N bits by dividing a reference voltage. A plurality of high-bits side comparators(11-1 to 11-7) are used for comparing the input voltage with each partial voltage. Each partial voltage is in a part of the plural partial voltages, which becomes data of high bits whose bit number is more than half of the N bits. A high-bits side encoding circuit(20) encodes the comparison results from the high-order comparators and outputs the encoded comparison results as high-bit data having the bit number of the high bits. A plurality of selection circuits(16-1 to 16-3) are used for selecting a part of the partial voltages, which becomes data of low bits with a bit number being defined as half of the plurality of N bits, in accordance with the comparison results of the high-bits side comparators. A plurality of low-bits side comparators(13-1 to 13-3) are used for comparing each partial voltage of the partial voltages selected by the selection circuits with the input voltage. A low-bits side encoding circuit(30) encodes the comparison outputs from the low-bits side comparators and outputs the encoded comparison results as low-bit data having the bit number of the low bits. A logic circuit(40) outputs N bits data based on a matching being made between the high-bit data and the low-bit data. When the matching stands between the high-bit data and the low-bit data, the N bits data are outputted in accordance with predetermined conditions. When the matching does not stands therebetween, the high-bit data are modified according to the low-bit data and the N bits data are outputted in accordance with predetermined conditions.
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