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:
Oct. 08, 2002
Filed:
Feb. 02, 1999
Frank Jeske, St. Georgen, DE;
Hermann Rappenecker, Vöhrenbach, DE;
Papst-Motoren GmbH & Co. KG, St. Georgen, DE;
Abstract
A watchdog circuit for a microprocessor which has a reset input and a control output, which output, when operation is normal, periodically delivers, under program control, a signal (P B ) of predefined duration (t ); and having a capacitor ( ) that can be charged via a charging circuit; having a discharging circuit ( ), controlled by the control output, for said capacitor ( ), for periodic discharge thereof during the predefined duration (t ); the charging circuit and discharging circuit being adapted to the program sequence of the microprocessor such that when the microprocessor is operating normally, charging of the capacitor via the charging circuit corresponds respectively to discharge thereof via the discharging circuit; so that the voltage at said capacitor rises and falls within a predefined voltage range; and having an apparatus ( ), for monitoring the charge state of said capacitor ( ), which, in the presence of a charge state thereof that does not occur in normal operation, effects a reset operation in the microprocessor.