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. 26, 2011
Filed:
May. 14, 2008
Toshiki Kishioka, Osaka, JP;
Yohichi Shiwaya, Osaka, JP;
Toshiki Kishioka, Osaka, JP;
Yohichi Shiwaya, Osaka, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A load driving circuit is disclosed that allows a charge pump circuit to operate at an optimum step-up ratio without frequently changing the step-up ratio. The load driving circuit includes a step-up circuit; a current setting circuit that sets a value of an electric current to be supplied to a load; a constant current circuit generating a constant electric current having the set value; a determination circuit; and a control circuit. In response to a load current setting signal, the current setting circuit sets the electric current to be maximum, and decreases the electric current step by step down to a preset value. Each time the electric current is decreased by one step, the control circuit changes the step-up ratio according to the determination results of the determination circuit, until the constant current circuit supplies the set electric current.