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. 22, 1983
Filed:
Aug. 18, 1981
Jack A Dorler, Wappinger Falls, NY (US);
Joseph M Mosley, Hopewell Junction, NY (US);
Richard O Seeger, Wappinger Falls, NY (US);
Stephen D Weitzel, Poughkeepsie, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A driver circuit for a capacitively loaded line employs the charge storage capacitance of a diode for raising the base of a driver transistor above the circuit power supply voltage level so as to pull up the line to within a transistor base-emitter voltage drop of the power supply voltage level. The driver is easily fabricated in integrated circuit form, as no capacitors, either on or off chip, are required. The driver circuit includes a driver transistor, the collector of which is connected to the power supply and the emitter of which is connected to the line. A switching transistor has an input voltage applied between its base and emitter. A diode is connected between the switching and driver transistors, the anode being connected to the base of the driver transistor, and the cathode being connected to the collector of the switching transistor. In response to a first input signal, the switching transistor turns on, forward biasing the diode and building up a voltage thereon as a result of the diode's charge storage capacitance. In response to a second input signal, the switching transistor turns off, raising the anode to the power supply voltage, and raising the cathode (and the base of the driver transistor connected thereto) to a voltage higher than the power supply voltage. The emitter of the driver transistor (and the line connected thereto) is thus pulled up to a value nominally approaching the power supply voltage, despite the base-emitter voltage drop of the driver transistor.