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:
Sep. 15, 1981
Filed:
Jul. 07, 1980
Rangaswamy Arumugham, Acton, MA (US);
GTE Laboratories Incorporated, Waltham, MA (US);
Abstract
A compensated reference voltage source for providing a stable output voltage despite variations in operating voltage. The circuitry includes a series arrangement of a first resistance, a Zener diode, and a second resistance connected between a source of operating voltage and ground. A first transistor has its collector connected to the juncture of the first resistance and the Zener diode, its base connected to the juncture of the Zener diode and the second resistance, and its emitter connected to ground. A second transistor has its base and emitter connected directly to the corresponding electrodes of the first transistor and its collector connected to an output terminal. A third transistor has its collector connected to the source of operating voltage, its emitter connected to the output terminal, and its base connected to the collector of the first transistor. The base-emitter characteristics of the transistors are essentially identical. The voltage across the Zener diode remains constant despite variations in the operating voltage. However, the voltage at the collector of the first transistor varies because of changes in current flow across its base-emitter junction. Because of the interconnections, equal currents flow through each of the transistors. Since the base-emitter characteristics of the transistors are identical, the voltage drops across the base-emitter junctions of the first and third transistors are equal. Thus, the voltage at the output terminal is equal to the voltage across the Zener diode and remains constant despite variations in the operating voltage.