| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high-precision digital output by comparing the total of standard currents of all high-order bits whose digital output which is already determined is 1 and standard currents corresponding to the bits of a digital output to be determined with an analog input. SOLUTION: When the most significant digit bit is 1, a PFET: 17 turns on for a next high-order bit and the standard current of the most significant bit is subtracted from the input current supplied from a PFET: 12. The standard current of the high-order 2nd bit is supplied from a standard current source 23 so as to subtract the standard current of the high-order 2nd bit from the current which is thus processed. The digital output of the 2nd bit is 1 when the input of an inverter 15 is at a high potential. Standard currents from (n-1) standard current sources controlled corresponding to the digital output of (n-1) high-order bits and the standard current of an (n)th bit are subtracted from the input current to determine the digital output of the (n)th bit.
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