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:
Sep. 05, 1995
Filed:
Jun. 29, 1993
Atsushi Kanke, Hitachi, JP;
Katsuji Marumoto, Hitachi, JP;
Keiichi Mashino, Katsuta, JP;
Yuuji Maeda, Hitachiota, JP;
Shouju Masumoto, Hitachiota, JP;
Naoyuki Takahashi, Katsuta, JP;
Shuuichi Kokubun, Naka, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Automotive Engineering Co., Ibaraki, JP;
Abstract
A control device for a battery charging AC generator for a motor vehicle including a power transistor connected in series with a field winding of the AC generator for performing switching control of a current flowing through the field winding. A voltage deviation circuit detects a deviation of the battery voltage from a reference voltage; and a PWM signal generating circuit is responsive to a voltage deviation signal from the voltage deviation circuit for turning the power transister on and off a resistor connected in series with the power transistor detects a current flowing through the field winding; and a current limiting circuit generates a turn off signal for the power transistor when the detected current is determined to have exceeded a reference current. A latch circuit operates in response to a clock signal from the PWM signal generating circuit to limit the frequency of turning on and off of the power transistor to below 1 KHz.