Teac Corporation

Tadashi Terada

Hiroshi Tsuyuguchi

Miya Enami

Naoki Sugeta

Tohro Miura

Yoji Abe

In order to drive the stepper motor of a floppy disk drive with practically constant current in the face of fluctuations in supply voltage fed from a host system, a power control pulse generator circuit is provided which produces a series of power control pulses having a duty ratio dependent upon fluctuating supply voltage. The power control pulses are used for interrupting the excitation of the stepper motor windings during track seek operation. The power control pulses are generated by first repeatedly counting clock pulses from the host system to a predetermined number to provide periodically varying digital data, then translating the digital data into a triangular wave having an amplitude dependent upon the supply voltage, and then comparing the triangular wave with a reference voltage.

Constant current driving system for a stepper motor in rotating disk

This invention is regarded to a pulley of a belt drive mechanism. The belt drive mechanism is applied to, for example, magnetic disk apparatuses. The contact surface of the pulley, in contact with a belt of the belt drive mechanism, has a shape of a part of a surface of a sphere. A center of a sphere is at a point substantially the same as a point of intersection of a plane including a center line of an operating course of the belt and a center line of rotation of the pulley.

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Tanashi, Japan

Tadashi Terada