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:
Mar. 11, 1997
Filed:
Nov. 24, 1995
Thomas R DeShazo, Frenchtown, NJ (US);
Other;
Abstract
A method and apparatus for stopping the operation of a failed device and preventing that device from being turned back on is shown, using two thresholds, a first failure threshold is shown when the device may be turned off or prevented from further operation. A second safe operation threshold is shown, different from the first threshold and within the safe operation range of the device. As the temperature rises, this transistor is driven further to conduction diverting base current from a second transistor and driving it further into nonconduction. The collector current from the second transistor is diverted to a resistor providing additional bias to the temperature sensitive transistor and driving it to a new bias. This bias establishes the second threshold. According to the inventive principles, the device is prevented from being turned back on until the safe operating threshold is reached. Further, a second condition requiring the reset signal for the device to be cycled through one complete cycle from off to on is shown. In the preferred embodiment, a temperature sensitive transistor is shown having a negative temperature coefficient.