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. 13, 1991
Filed:
May. 22, 1990
John G Banaska, Brunswick, OH (US);
Keithley Instruments, Inc., Cleveland, OH (US);
Abstract
An apparatus capable of acting as a current-limited voltage source or a voltage-limited current source is disclosed. The output of the apparatus is provided by a differential amplifier. The current and voltage outputs are compared to positive and negative current and voltage limits. Depending on whether the apparatus is in the voltage mode or the current mode, the inverting input of the differential amplifier is clamped to the appropriate voltage or current comparison signal, respectively, to provide an error signal to the differential amplifier. This clamping is current limited so that if the output current limits are exceeded while in the voltage source mode, a clamp to one of the current comparison signals occurs and dominates the voltage clamp. Similarly, if the output voltage limits are exceeded while in the current source mode, a clamp to one of the voltage comparison signals occurs and dominates the current clamp. To enable a voltage or current source limit to be set at zero, the opposite polarity limit is offset slightly to avoid contention should it also be set near zero.