公开(公告)号：JPH11205143A

公开(公告)日：1999-07-30

申请号：JP13237098

申请日：1998-05-14

Applicant: UNITED MICROELECTRONICS CORP

Inventor： CHO KUNKO

IPC: H03M1/34 ,  H03M1/42

Abstract: PROBLEM TO BE SOLVED: To convert an analog signal into a digital signal without requiring any timing signal for converting operation by feeding the respective data buts of a digital output back to a reference voltage supply circuit for determining the data but of the digital output at series of time intervals. SOLUTION: A three-bit A/D converter is provided with the array of three comparators 40-42. All the non-inverted inputs of the comparators 40-42 are mutually linked and the same analog input signal Vin to be converted into digital data is supplied. To inverted inputs 43-45 of the comparators 40-42, respectively correspondent reference voltages are supplied. The compared outputs of the comparators 40-42 are used as respective digital converted output bits Q2-Q0. The comparators 40-42 have the inverted inputs to which correspondent reference voltages Vref2 -Vref0 are supplied, respectively. These reference voltages are used by the comparators 40-42 for respectively executing comparison with the analog signal Vin.