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. 17, 1996
Filed:
Mar. 01, 1995
Tomoyuki Yamazaki, Nagano, JP;
Shigeyuki Obinata, Nagano, JP;
Fuji Electric Co., Ltd., Tokyo, JP;
Abstract
For stabilized overcurrent protection, an insulated-gate type bipolar transistor (IGBT) is provided with an overcurrent limiting feature having reduced dependence of the limited-current value on the power supply voltage. Sensing cells 9 for current detection are formed on part of a semiconductor substrate 5 on which a large number of IGBT main cells 6 are formed integratedly. Emitter electrodes 10 of the sensing cells are connected to an external overcurrent-protection circuit for current detection and overcurrent protection. The sensing cells and the main cells are electrically separated. P-wells 11 for drawing out hole current, connected to the emitter electrodes of the main cells, are formed in a region along the circumference of the sensing cells so that interference between the carriers of the main cells and those of the sensing cells is suppressed and current ratio is stabilized.