Patent ID: 7834567

Claim:
A motor drive device for alternately driving a plurality of motors, which motor drive device comprising: a motor switching circuit for generating a signal instructing a switchover of driving the plurality of motors; a position detection signal processing circuit configured to (i) receive position detection signals from the plurality of motors and the signal from the motor switching circuit and (ii) generate a position detection processed signal based on the position detection signals and the signal from the motor switching circuit; a pre-drive circuit configured to receive the position detection processed signal and generate an excitation switching signal for the plurality of motors; a plurality of power switching circuits configured to (i) receive the excitation switching signal from the pre-drive circuit and (ii) supply an electric current based on the excitation switching signal from the pre-drive circuit to at least one of the plurality of motors, wherein the position detection signal processing circuit selects, in response to an input to the motor switching circuit, a position detection signal of one of the motors to be driven out of the position detection signals of the plurality of motors, and inputs a position detection processed signal to the pre-drive circuit, and then one of the plurality of power switching circuits is selected for driving the motor to be driven.