| 摘要 |
PROBLEM TO BE SOLVED: To accurately control the current consumption of a comparator circuit and the current consumption of a reference voltage generating circuit corresponding to the converting speed of an A/D converter for allowing the A/D converter to operate accurately corresponding to the converting speed with the absolute minimum current consumption. SOLUTION: A current consumption controller 28A is provided with the current control circuits of the chopper comparators of a comparator circuit 21 for upper 4 bits and comparator circuits 22 and 23 for lower 4 bits and the current control circuit of a reference voltage generating circuit 24A. Thus, the chopper comparators and the reference voltage generating circuit 24A can be driven in either a normal operation state or a low current consumption operating state respectively according to the combination of control signals Vc1 and STB and the combination of control signals Vc2 and STB. Thus, the highly precise A/D converting operation can be accurately and efficiently attained in the operating state without any useless power consumption according to the converting speed by selecting the operation mode corresponding to the converting speed of the A/D converter.
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