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:
Jul. 22, 2008
Filed:
Aug. 18, 2006
Takashi Sase, Hitachi, JP;
Akihiko Kanouda, Hitchinaka, JP;
Yosuke Kawakubo, Odawara, JP;
Kozaburo Kurita, Ohme, JP;
Takashi Sase, Hitachi, JP;
Akihiko Kanouda, Hitchinaka, JP;
Yosuke Kawakubo, Odawara, JP;
Kozaburo Kurita, Ohme, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An over-current detection circuit using the ON-voltage of a main MOSFET is provided, which is resistant to process variations of a main MOSFET and is not easily influenced by switching noise. Separately from a main MOSFET (Q), a sense MOSFET (Q) whose size is 1/m of the main MOSFET is provided and it is caused to be normally on. A DC ON-voltage generated when a current that is 1/m of an over-current value is caused to flow through the sense MOSFET is obtained as a reference voltage for over-current setting. The ON-voltage when the main MOSFET is on is sampled and held, and it is obtained as a DC voltage. These DC voltages are compared in a comparator (COMP).