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. 08, 2007
Filed:
Dec. 22, 2004
Haruo Kamijo, Suwa, JP;
Haruo Kamijo, Suwa, JP;
Seiko Epson Corporation, , JP;
Abstract
A comparator circuit includes a current mirror circuit, a differential pair, and a first current source between first and second power supply lines. The differential pair includes a first MOS transistor of enhancement mode n-type having a gate electrode at which an input signal is supplied, and a second MOS transistor of depletion mode n-type. A source of the second MOS transistor is connected with a source of the first MOS transistor and a threshold voltage of the second MOS transistor is lower than that of the first MOS transistor. A gate electrode of the first MOS transistor is formed by polycrystalline silicon which contains a p-type impurity. A gate electrode of the second MOS transistor is formed by polycrystalline silicon which contains an n-type impurity and is connected with the first power supply line. An output signal is output based on a drain voltage of the second MOS transistor.