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. 09, 2010
Filed:
Nov. 09, 2007
Masataka Sasaki, Hitachi, JP;
Katsumi Ishikawa, Hitachinaka, JP;
Ryuichi Saito, Hitachi, JP;
Koichi Suda, Mito, JP;
Katsuaki Takahashi, Hitachiota, JP;
Masataka Sasaki, Hitachi, JP;
Katsumi Ishikawa, Hitachinaka, JP;
Ryuichi Saito, Hitachi, JP;
Koichi Suda, Mito, JP;
Katsuaki Takahashi, Hitachiota, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A collector voltage of a power management semiconductor device is detected by a first comparator, and when the detected collector voltage exceeds a first reference voltage, the first comparator outputs a first detection signal. Furthermore, a gate voltage of the power management semiconductor device is detected by a second comparator, and when the detected gate voltage exceeds a second reference voltage, the second comparator outputs a second detection signal. The second reference voltage is a minimum gate voltage for feeding a rated power to the power management semiconductor device or over, and less than a line power voltage of a drive circuit of the power management semiconductor device. When both the first detection signal and second detection signal are being outputted, the gate voltage is reduced by a gate voltage reduction means so as to protect the power management semiconductor device from overcurrent and overvoltage.