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. 30, 1994
Filed:
Jun. 09, 1992
John G Metro, Kingston, RI (US);
Denis P Galipeau, Woonsocket, RI (US);
Cherry Semiconductor Corporation, East Greenwich, RI (US);
Abstract
A transistor overcurrent protection circuit using an error amplifier to make a voltage comparison between a threshold voltage and the collector voltage of a current sensing transistor. The current sensing transistor is arranged in a circuit such that the collector current of the current sensing transistor is a measure of the collector current of an output transistor. A driver transistor has its emitter connected to the base of the output transistor. A source of control current to the drive transistor is coupled to the output of the error amplifier. When the collector voltage of the current sense transistor falls below the threshold voltage, the error amplifier causes the control current to the drive transistor to be reduced so as to reduce the collector current of the output transistor.