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:
Dec. 20, 1994
Filed:
Feb. 17, 1993
Masaaki Taruya, Himeji, JP;
Mitsuru Koiwa, Himeji, JP;
Mitsubishi Denki K.K., Tokyo, JP;
Abstract
An ignition apparatus for an internal combustion engine having a current limiting function is simple in construction and can avoid variations In the current limiting values for respective power transistors 103. A current limiting circuit 109 includes a common resistor 105 connected at one end thereof to a power supply 101 and at the other end thereof to a plurality of ignition voltage generating circuits 104. an operational amplifier 107 making a comparison between a voltage V.sub.105 across the resistor 105 and a reference voltage Vr which corresponds to a predetermined upper limit current for each power transistor 103 and generating an output signal A of a magnitude proportional to a difference (V.sub.105 -Vr) therebetween, and a plurality of transistors 108 provided one for each power transistor 103 and connected to receive the output signal A from the operational amplifier 107 for limiting a current through a corresponding power transistor 103 in response to the output signal A. The current limiting circuit 107 serves to sense a current flowing through each power transistor 103 and limit it to a predetermined upper limit value to thereby protect each power transistor from damage due to an overcurrent therethrough.