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. 24, 1989
Filed:
Oct. 16, 1986
James T Libert, Waukesha, WI (US);
Square D Company, Palatine, IL (US);
Abstract
A gate drive circuit for a thyristor has a power supply and an amplifier for supplying current to a gate electrode of the thyristor. A timing signal is generated to initiate conduction of the thyristor. A voltage level signal is generated in response to a voltage from cathode to anode of the thyristor to indicate a reduction in the cathode to anode voltage of the thyristor when the voltage is reduced by conduction of the thyristor. Current is supplied to the gate electrode of the thyristor in response to the timing signal, and current ceases to flow to the gate electrode of the thyristor at a predetermined time interval following generation of the voltage level signal indicative of a collapse in cathode to anode voltage of the thyristor caused by conduction of the thyristor, and the predetermined time interval is chosen to be of sufficient duration to permit conduction of the thyristor to reach a stable value before current flow to the gate electrode of the thyristor substantially ceases.