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:
Oct. 28, 2008
Filed:
Nov. 11, 2004
Hiroshi Katsunaga, Kariya, JP;
Hiroshi Miyagi, Joetsu, JP;
Hiroshi Katsunaga, Kariya, JP;
Hiroshi Miyagi, Joetsu, JP;
Kabushiki Kaisha Toyota Jidoshokki, Kariya-Shi, JP;
Niigata Seimitsu Co., Ltd., Joetsu-Shi, JP;
Abstract
It is an object of the present invention to provide a variable gain amplifier circuit operable with a low power supply voltage and with less noise generated inside the circuit. In the variable gain amplifier circuit, a third MOS transistor is connected between the respective sources of two MOS transistors constituting a differential amplifier circuit and to the gate of the third MOS transistor, and a DC bias voltage for operating the third MOS transistor in a non-saturated region is supplied. If the output voltage of an AM intermediate frequency variable gain amplifier circuit increases, a control voltage for reducing the resistance between the source and drain of the third MOS transistor is applied to reduce the gain of the AM intermediate frequency variable gain amplifier circuit.