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. 17, 1998
Filed:
Feb. 07, 1995
Yoshifumi Tomomatsu, Fukuoka, JP;
Youichi Ishimura, Fukuoka, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
It is an abject to stably and surely perform protection operation of devices. Since the gate threshold voltage V.sub.GE(th)S in a sense IGBT cell constituting a sensing circuit is set to have a higher value than the gate threshold voltage V.sub.GE(th)M in a main IGBT cell constituting a main circuit, a finite time .DELTA.t is required from when the gate voltage V.sub.GE reaches the gate threshold voltage V.sub.GE(th)M until when it reaches the gate threshold voltage V.sub.GE(th)S in the turn-on period. Accordingly, the rise of the main current Is of the sensing circuit is delayed from the main current Im of the main circuit. As a result, surge current does not appear in the current Is. As the surge current does not appear in the main current of the sensing circuit, a protection circuit of the device operates stably, and breakdown of the device is surely prevented.