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. 24, 1996
Filed:
Mar. 09, 1995
Kiyoshi Kase, Chiba, JP;
Motorola, Inc., Schaumburg, IL (US);
Abstract
An overcurrent is detected with small power consumption and at a high level of accuracy. A first transistor section 3 comprised of one NPN transistor 31 and a second transistor section 4 comprised of four NPN transistors 41-44 having the same characteristics as those of the transistor 31 are connected across a current sense resistor 2, with their emitters connected to the resistor 2. The transistors 31 and 41-44 have their bases commonly connected, with a voltage applied between their base and emitter by a voltage application unit 5, and have their collectors connected to transistors 61 and 62 which form a current mirror circuit. Once a bandgap voltage, .DELTA.V.sub.BE, i.e., a voltage difference between the base-emitter voltages of the transistor sections 3 and 4, is determined, the current density ratio of both the transistor sections 3 and 4 is determined, which is used to detect an overcurrent.