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:
Mar. 04, 2003
Filed:
Feb. 26, 2001
Stephane Guenot, Grass Valley, CA (US);
Jeffrey P. Kotowski, Nevada City, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A band gap circuit that may be implemented in a standard CMOS process including a pair of parasitic vertical PNP transistors operating at a different current density. The PNP transistors have common collectors and common bases and produce a difference in base-emitter voltages which is developed across a resistor so as to produce a current having a positive temperature coefficient. The current is used to produce a positive temperature coefficient voltage which is combined with another voltage having a negative temperature coefficient to produce a band gap reference voltage. A bias voltage is applied between the base and collector of each of the PNP transistors, typically on the order of 500 millivolts. This causes the emitters of the PNP transistors to be at a voltage which can be sensed by an error amplifier implemented with standard N type MOS input transistors while maintaining a capability of operating using a relatively low power supply voltage.