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:
Oct. 16, 1984
Filed:
Mar. 01, 1982
Hiromitsu Nakano, Katano, JP;
Isao Yoshida, Suita, JP;
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
A speed control apparatus for DC motor (1), comprises a bridge circuit formed by the winding of the motor (1), a resistor (2) series thereto, and two resistors (3 and 4). Therein, a reference voltage (E.sub.r) is produced by dividing a voltage V.sub.ref of a constant voltage circuit (20) by a divider network (21+22). The voltage difference this reference voltage (E.sub.r) and a voltage produced across the detection output terminals 'a' and 'b' which is proportional to a counter electromotive force (E.sub.a) of the DC motor (1) is amplified by a differential amplifier (23+24). A current mirror circuit is formed by transistors (16), (17) and (18). The first transistor (16) regulated of its collector current (I.sub.r) by a constant current circuit (19) controls collector current of the second transistor (17), which controls input current of the constant voltage circuit (20). The third transistor (18) regulated of its collector current constantly controls the input current to the differential amplifier (23+24) for controlling the transistor (7) to control the motor current.