Tomoki Yokoyama

Title: Tomoki Yokoyama: Innovator in Spindle Motor Control Technology

Introduction

Tomoki Yokoyama is a notable inventor based in Higashine, Japan. He has made significant contributions to the field of spindle motor control, holding 2 patents that showcase his innovative approach to enhancing motor performance.

Latest Patents

Yokoyama's latest patents include a spindle-motor control method, spindle-motor control device, spindle-motor drive circuit, and disk device. This invention focuses on a control method, control device, and drive circuit designed to manage the rpm of a spindle motor effectively. The goal is to reduce the rise time of the spindle motor. The invention features a discharge circuit within the charge pump of a spindle-motor driver. A control circuit detects when the spindle motor's rpm approaches a target value and discharges the charge pump accordingly. This process helps to minimize rotation errors near the target rpm, allowing for better control and suppression of overshoot, ultimately leading to a reduced rise time.

Another significant patent involves a motor driving device, a method of adjusting the same, and an information storage device. This invention provides a method for adjusting a motor driving device that utilizes current-feedback PWM drive. The drive circuit is turned off by a control circuit, and a target current indication signal is gradually increased. The content of a register, which stores the results of comparisons between the output signal of a comparator circuit and the target current indication signal, is then detected. If the register's content indicates that the output signal is smaller than the target current indication signal, the target current indication signal immediately before the comparator circuit output reaches '1' is stored as the reference value.

Career Highlights

Tomoki Yokoyama is currently employed at Fujitsu Corporation, where he continues to develop innovative technologies in motor control. His work has significantly impacted the efficiency and performance of spindle motors in various applications.

Collaborations

Yokoyama collaborates with esteemed colleagues, including Masatsugu Nishida and Toru Ikeda, who contribute to his research and development efforts.

Conclusion

Tomoki Yokoyama's contributions to spindle motor control technology reflect his dedication to innovation and excellence in engineering. His patents not only enhance motor performance but also pave the way for future advancements in the field.