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. 12, 2004
Filed:
Feb. 05, 2003
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
In a negative voltage output charge pump circuit, first a capacitor C is charged with a positive voltage Vin relative to a reference voltage, and then the high-potential terminal A of the capacitor C is made to conduct to the reference voltage and simultaneously the low-potential terminal B of the capacitor C is made to conduct to an output terminal OUT so that the voltage with which the capacitor C is charged is output as a negative voltage −Vin. Here, at least one of the switching device DP that is kept on while the capacitor C is being charged so as to apply the reference voltage to the point B and the switching device DP that is kept on while the negative voltage is being output so as to make the point B conduct to the output terminal OUT is a depletion-type transistor. This configuration makes it possible to realize a negative voltage output charge pump circuit that is free from malfunctioning caused by a parasitic device, that operates with low loss, and that can be produced at low costs.