The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 13, 1989
Filed:
Feb. 26, 1987
Bipin V Gami, Chatsworth, CA (US);
Ericson Dunstan, Port Hueneme, CA (US);
Micropolis Corporation, Chatsworth, CA (US);
Abstract
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.