Comparator

摘要

A comparator is constructed to exclude an adverse effect of variation of a power source potential VDD or the like on a current output Iout. The comparator comprises a first voltage follower portion which receives an input potential Vin and outputs a potential (=Vin) following the input potential, a second voltage follower portion which receives a reference voltage Vref and outputs a potential (=Vref) following the input potential, and a current subtracting portion which outputs as a comparison result (Iout) a value achieved by subtracting the amount of current flowing due to the potential difference between the power source potential VDD of the comparator and the output potential (=Vref) of the second voltage follower portion from the amount of current flowing due to the potential difference between the power source potential VDD of the comparator and the output potential (=Vin) of the first voltage follower portion.