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:
Nov. 29, 1994
Filed:
Jan. 29, 1993
Franciscus A Schoofs, Eindhoven, NL;
Johan C Halberstadt, Nijmegen, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A power transistor switching circuit includes a switching transistor. A switching signal triggers a control device which, via a delay device and a control amplifier applies a first control signal to a control electrode of the switching transistor. A thyristor is coupled to the control electrode of the switching transistor. The thyristor has a first trigger gate and a second trigger gate. A measuring circuit generates a measuring signal proportional to the current in the switching transistor. A comparison device compares the measuring signal with a reference signal for applying a second trigger signal to the thyristor second trigger gate. The control device includes a further control amplifier having an input coupled to the switching signal and an output which applies a further control signal to the first trigger gate. The delay device delays the first control signal with respect to the further control signal. When the switching transistor is turned on, the further control amplifier and the delay device prevent unwanted triggering of the thyristor due to the high impedance of the signal source which supplies the second trigger signal.