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. 16, 2007
Filed:
Apr. 26, 2005
Haruo Suenaga, Osaka, JP;
Hideaki Moriya, Nara, JP;
Shinichi Sakai, Nara, JP;
Hisashi Morikawa, Nara, JP;
Nobuo Shirokawa, Nara, JP;
Manabu Kinoshita, Nara, JP;
Haruo Suenaga, Osaka, JP;
Hideaki Moriya, Nara, JP;
Shinichi Sakai, Nara, JP;
Hisashi Morikawa, Nara, JP;
Nobuo Shirokawa, Nara, JP;
Manabu Kinoshita, Nara, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A purpose of the present invention is to provide an inverter circuit capable of firmly turning ON IGBTs under limited condition, while a heat loss and noise can be hardly produced in semiconductor switching elements. In a resonant type high frequency heating apparatus which is arranged by employing a DC power supply; a series connection circuit constructed of two semiconductor switching elements which are connected to the DC power supply; another series connection circuit constituted by a capacitor and a primary winding of a leakage transformer connected to both the terminals of one of the two semiconductor switching elements; and a driving means for driving the respective semiconductor switching elements respectively, a variable dead time forming circuit is provided in the driving means, while the variable dead time forming circuit makes a dead time constant at a switching frequency lower than, or equal to a predetermined switching frequency, and also, rapidly increases a dead time at a switching frequency higher than, or equal to the predetermined switching frequency. Furthermore, when the switching frequency becomes high, a limitation is provided by which the dead time is not further widened.