Drive circuit for brushless DC motors

摘要

A drive circuit for a brushless DC motor capable of generating a torque in the acceleration and deceleration directions, respectively, and effective when used in a portable device such as an electronic still picture camera. In the drive circuit, a power amplifier having an output stage composed of a pair of complementarily connected tansistors is connected to each end of each of the stator coils. Thus, the drive circuit controls the input potentials of the power amplifiers so as to produce a potential difference across the terminals of each of the stator coils and thereby control the magnitude and direction of current flow through the stator coils. Also, all the transistors of the power amplifier output stages are cut off to prevent the flow of current through the stator coils.