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:
May. 27, 2003
Filed:
Oct. 05, 2001
Masuhide Ikeda, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
The invention provides an operation amplification circuit and the like that can reduce current consumption, is not dependent on the power supply voltage, and can suppress mass-production variations. The present invention is equipped with a bias circuit, a differential amplification circuit and an output amplification circuit. The bias circuit includes a reference voltage circuit and a current mirror circuit. The reference voltage circuit includes a depletion type PMOS transistor and an enhancement type PMOS transistor serially connected to each other. The MOS transistor has a gate electrode that is formed from polysilicon including a P-type impurity, and the MOS transistor has a gate electrode that is formed from polysilicon including an N-type impurity. Furthermore, a voltage corresponding to a difference between threshold voltages of the MOS transistors is generated at a commonly connected section of the MOS transistors as a reference voltage.