초록 ▼

An improved switching regulator power supply with a variable duty cycle is disclosed which forms part of a compact Winchester disk drive system having a storage capacity in excess of 380M bytes of information. The switching regulator is designed for frequencies in excess of 80 kilocycles per second

An improved switching regulator power supply with a variable duty cycle is disclosed which forms part of a compact Winchester disk drive system having a storage capacity in excess of 380M bytes of information. The switching regulator is designed for frequencies in excess of 80 kilocycles per second and may therefore be construced using smaller capacitive and inductive elements. Also, very low heat dissipation and high regulator efficiency may be achieved by the improved power supply to drive a brushless D. C. motor encased within a hard disk assembly where no separate fan or cooling system is used to aid in heat removal. Circuitry is provided to control the motor speed while simultaneously limiting the motor current to a predetermined level. This is a achieved by controlling the voltage applied to the motor by suitably adjusting the duty cycle of the switching regulator. A filter is provided to ensure that the switching regulator current fluctuations are not reflected in the current drawn from the power supply. At the start when the D. C. motor E.M.F. is zero, the switching regulator causes significantly higher current to flow through the motor than is drawn from the power supply through a current multiplying effect. These unique features provides significant advantages in a Winchester disk drive using thin film media whose overcoming high level of initial stiction-friction forces is important and desirable.

대표청구항 ▼

A hard disk drive system comprising: a head positioner; a hard disk drive assembly; a DC motor, having a fixed stator surrounded by a movable rotor, for driving said disks; a DC power supply; a switching regulator means; means including a series inductor and a shunt capacitor for coupling said switc

A hard disk drive system comprising: a head positioner; a hard disk drive assembly; a DC motor, having a fixed stator surrounded by a movable rotor, for driving said disks; a DC power supply; a switching regulator means; means including a series inductor and a shunt capacitor for coupling said switching regulator means to said DC power supply; motor drive circuit means for driving said DC motor; said motor drive circuit means receiving a regulated supply of voltage from said switching regulator means; a motor drive logic means for sequentially activating said motor drive circuit means, said motor drive logic means including motor position sensing means; a motor speed controller means for establishing an error signal representative of the difference between a desired reference speed and actual motor speed; a duty cycle controller means for providing pulse width modulated control of said switching regulator means; a variable set-point current limiting means, including means for varying the set-point to control the current flow to said motor; said duty cycle controller means including means for providing a stable high frequency duty cycle control signal to said switching regulator means which is a function of (1) said error signal of said motor speed controller means and (2) the output of a variable set-point current limiting means; current sensing means, connected between said motor drive circuit means, and said variable set-point current limiting means, for sensing the amount of current drawn by said DC motor, and said current sensing means including means for providing feedback to said current limiting means, to shift the set-point of said duty cycle controller, thereby changing the duty cycle of said switching regulator.