Novel two-phase spindle motor for digital video disk applications

Disk drives require high-precision spindle motors for fast and accurate access of data. This paper presents a new two-phase spindle motor for digital video disks (DVDs) and compact disks (CDs). The brushless spindle motor has a pancake-type construction, which has distinct advantages and costs less to manufacture because of the simplicity of the stator structure and the windings. The constraint between the detent torque and the starting torque in the single-phase pancake-type motor design is resolved by using the two-phase scheme. A prototype of the two-phase spindle motor and drive circuit has been made and tested in commercial DVD and CD-ROM drives. Experimental results show that its performance satisfies the requirements of the optical disk drives.