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:
Jun. 10, 2008
Filed:
Jan. 10, 2007
Takuya Ishigaki, Hitachi, JP;
Takashi Sase, Hitachi, JP;
Akihiko Kanouda, Hitachinaka, JP;
Koji Tateno, Takasaki, JP;
Ryotaro Kudo, Takasaki, JP;
Takuya Ishigaki, Hitachi, JP;
Takashi Sase, Hitachi, JP;
Akihiko Kanouda, Hitachinaka, JP;
Koji Tateno, Takasaki, JP;
Ryotaro Kudo, Takasaki, JP;
Renesas Technology Corp., Tokyo, JP;
Abstract
In a switching power supply apparatus for performing a switching control of a power MOS transistor that flows current to a coil and converting input voltage into output voltage, even if there occurs offset voltage in a current sensing operational amplifier, source potential of a current sensing MOS transistor is precisely kept at source potential of a low side power MOS transistor. For example, an offset cancel capacitor is arranged at an inverting input terminal of the current sensing operational amplifier, and voltage in the direction to offset the offset voltage occurring in the operational amplifier is charged to this capacitor.