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:
Jan. 18, 1994
Filed:
Sep. 03, 1992
Tatsuhisa Fujii, Mobara, JP;
Iwao Takemoto, Mobara, JP;
Atsushi Hasegawa, Mobara, JP;
Kenji Kitajima, Mobara, JP;
Tetsuro Izawa, Mobara, JP;
Katsumi Matsumoto, Mobara, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Device Engineering Co., Ltd., Chiba, JP;
Abstract
Herein disclosed is an amplification circuit for realizing a substantially high sensitivity with a simple structure. The amplification circuit comprises: a first capacitor C1 for receiving a signal charge; a source-follower circuit for receiving a voltage of the first capacitor C1; an inversion amplification circuit including a source-earth type amplification MOSFET Q5 having its gate fed with the output signal of the source-follower circuit through a second capacitor C2; a feedback third capacitor C3 connected between the gate and drain of the amplification MOSFET Q5; and a switch element Q6 for feeding the gate of the amplification MOSFET Q5 with a predetermined bias voltage while the signal charge of the first capacitor C1 is being reset. The amplification MOSFET Q5 has its drain equipped as load means with a depletion type MOSFET Q4 having its gate and source connected, and the depletion type MOSFET Q4 has its source given the same potential as the substrate potential thereof.