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:
Apr. 03, 1984
Filed:
Jun. 04, 1982
Michael J Hampshire, Liversedge, GB;
Salplex Limited, London, GB;
Abstract
A switching circuit has a solid state power switch (9) which is either a PNP or NPN transistor or a VMOS p- or n-channel device. Three individual sensing circuits (2, 3, 4) are set to indicate whether a predetermined operating characteristic of the switch (9) is greater or less than a given threshold value and thus to indicate if a fault is present in the switch (9) or the load (L) it supplies. Digital logic circuit means comprising three logic circuits (5, 6, 8) produce two digital signals from the output signals of the sensing circuits respectively indicating if a fault exists and if it is a serious fault or not. A circuit (7) comprising gating means disables the switch (9) in the event of a serious fault and a delay circuit (33, 34) is provided associated with the logic circuit means to prevent current surges due to short circuit faults being confused with normal operating current surges in switch on.