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:
Apr. 15, 1997
Filed:
Sep. 28, 1994
Tatsuhiko Fujihira, Nagano, JP;
Shin Kiuchi, Nagano, JP;
Kazuhiko Yoshida, Nagano, JP;
Yukio Yano, Nagano, JP;
Kazunori Oyabe, Nagano, JP;
Shoichi Furuhata, Nagano, JP;
Tetsuhiro Morimoto, Nagano, JP;
Fuji Electric Co., Ltd., Tokyo, JP;
Abstract
The disclosed invention is designed to prevent the oscillation which often occurs in an over-current protection apparatus for an insulated gate controlled transistor. The apparatus improves the response in current detection, to prevent oscillation, and improves protection speed against over-current. This is accomplished by separating the gates of the main transistor and the current detector transistor; by setting a shorter time constant for the gate circuit of the current detector transistor than that of the gate circuit of the main transistor; by feeding the detection signal obtained from the current detecting means which detects the current i of the current detector transistor proportional to the current I flowing through the main transistor, to the control means; and by controlling the gate potentials of both transistors to protect the main transistor from the over-current by feeding the comparison output Sd from the comparator circuit, which compares the voltage of the signal Vd with the reference voltage Vr, to the control circuit.