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:
Jan. 25, 1994
Filed:
Nov. 17, 1992
Timothy P Hulick, Schwenksville, PA (US);
Acrodyne Industries, Inc., Blue Bell, PA (US);
Abstract
The normally slow rise time of a Class C bipolar transistor grounded base RF power amplifier is greatly enhanced by circuitry external to the amplifier transistor. Current is injected into the base of the transistor for the duration of the rise time, biasing it into Class A operation during this period. Then, after the base current injection, operation reverts to Class C to retain amplifier power efficiency. Finally, the normally slow fall time of the bipolar Class C RF power amplifier is greatly enhanced by reverse-biasing the base-to-emitter junction during the fall time. During this fall time the amplifier is forced into its cutoff region by the applied reverse bias, as stored charge is pulled out of the base-emitter region of the transistor. In this manner, the power efficiency advantage of Class C power amplifiers may be retained, while adding the benefits of sharper output rise and fall times that would not otherwise be achieved.