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:
Jul. 08, 2003
Filed:
Sep. 27, 2001
Naohiro Ueda, Hyougo-ken, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A reference voltage generation circuit includes a depletion type MOS transistor having a gate connected to a source and functioning as a constant current source. At least two enhancement type MOS transistors are connected to the depletion type MOS transistor, and have different threshold voltages, but substantially the same profiles of channel impurities. A pair of floating gate and control gate may be provided in one of the two enhancement type MOS transistors. One of the thresholds is determined by a difference in a coupling coefficient calculated from an area ratio of the floating gate and control gate to a channel so as to avoid fluctuations in performance of the MOS transistors due to temperature.