AMPLITUDE REGULATION CIRCUIT INCLUDING VARIABLE GAIN AMPLIFIERS, MAXIMUM VALUE DETECTION UNIT, MINIMUM VALUE DETECTION UNIT, AND CONTROL SIGNAL GENERATING UNIT, AND AMPLITUDE REGULATION METHOD, AND MOTOR DRIVING CONTROL APPARATUS AND MOTOR DRIVING CONTROL METHOD

摘要

PURPOSE: An amplitude regulation circuit and an amplitude regulation method, and a motor driving control apparatus and a motor driving control method are provided to maintain a high automatic gain control(AGC) responsiveness and prevent signal distortions when a motor rotating speed is low. CONSTITUTION: An amplitude regulation circuit comprises variable gain amplifiers(21,22,23), a maximum value detection unit(11), a minimum value detection unit(12), and a control signal generating unit. The variable gain amplifiers correspond to a plurality of phases, and amplify signals of corresponding phases by using a gain controlled by a control signal, and output the amplified signal. The maximum value detection unit outputs a maximum value signal, on the basis of an amplified signal having a highest level from the amplified signals output from the variable gain amplifiers. The minimum value detection unit outputs a minimum value signal, on the basis of an amplified signal having a lowest level from the amplified signals. The control signal generating unit outputs a control signal to each of the variable gain amplifiers so as to decrease the gain when a difference between the maximum value signal and the minimum value signal is larger than a predetermined reference value, and outputs a control signal to each of the variable gain amplifiers so as to increase the gain when the difference is smaller than the predetermined reference value.