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:
Aug. 04, 1998
Filed:
Nov. 08, 1995
Kunihiro Abe, Higashi-Murayama, JP;
Fuji Jukogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A diagnosis system has a main circuit for executing diagnosis by data communication with an electronic control unit installed in a vehicle using data read out of the control unit. The system has an interface circuit that converts input and output signal levels on the main circuit sent from and to the control unit into signal levels that match signal levels in the control unit. The interface circuit has a comparator and a transistor. A signal sent from the control unit and pulled up with a supply voltage supplied to the control unit is applied to the comparator at its inverting input terminal. A reference signal based on the supply voltage is also applied to the comparator at its non-inverting input terminal. An output signal of the comparator is applied to the main circuit. The transistor is supplied with the supplied voltage via a resistor at its collector. The transistor receives at its base an output signal of the main circuit. A signal appearing at the collector is applied to the control unit. The system also has a switch provided on the main circuit. A supply voltage supplied to the interface circuit is switched between the supply voltage supplied to the control unit and a supply voltage supplied to the main circuit.