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:
Jan. 20, 1987
Filed:
Jan. 31, 1986
Shigeki Morinaga, Hitachi, JP;
Kunio Miyashita, Hitachi, JP;
Hiroshi Hayashida, Mito, JP;
Tadashi Takahashi, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A pulse width control apparatus and method for controlling motor speed wherein the number of pulses relating to more speed feedback data is counted so as to control the speed of the motor in accordance with a speed command data and a pulse width modulation signal based on the counted number of pulses. A free-running hardware timer and a soft-timer on a program controlled by an instruction execution time of a microcomputer are arranged so that ON-time data and OFF-time data of the pulse width modulation signal are selectively set in one and the other of the hardware and soft-timers in dependence on values of the ON and OFF times, respectively. The ON and OFF states of the pulse width modulation signal are changed when the contents of the hardware and soft-timers reach predetermined values so as to control the pulse width thereof.