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:
Mar. 18, 2008
Filed:
Apr. 21, 2006
Yuji Zushi, Tokyo, JP;
Shozo Kanazki, Tokyo, JP;
Yuji Zushi, Tokyo, JP;
Shozo Kanazki, Tokyo, JP;
Mitsubushi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A single state detector circuit can quickly detect short-circuit and open-circuit abnormalities of a load controlled by a power transistor. A DC power supply, the load and the power transistor are serially connected with one another, so that a switching terminal voltage of the power transistor is binarized into high and low levels by the state detector. The power transistor is linearly controlled by a constant-current control circuit so as to suppress an excessive current, and power supplied to the power transistor is interrupted by an overheat interruption circuit. Upon occurrence of a short-circuit in the load during generation of an energization command, a switching terminal voltage of the power transistor becomes stabilized at a high level without intermittent operation, which is detected by the state detector. Upon occurrence of an open-circuit during generation of a deenergization command, a low switching terminal voltage is detected by the state detector.