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:
Sep. 22, 2009
Filed:
Nov. 18, 2005
Tomoyuki Ito, Kyoto, JP;
Isao Yamamoto, Kyoto, JP;
Tomoyuki Ito, Kyoto, JP;
Isao Yamamoto, Kyoto, JP;
Rohm Co., Ltd., , JP;
Abstract
A driver circuit for a charge pump circuit capable of switching between step-up ratios, may include a control unit which controls the charge pump circuit; a first oscillator outputting a first periodic signal; and a second oscillator outputting a second periodic signal employed for a time measurement for setting the step-up ratio and having a frequency set lower than the first periodic signal. When the step-up ratio of the charge pump circuit is larger than 1, the control unit turns on only the first oscillator to perform, based on the first periodic signal, a time measurement for setting the step-up ratio and the control of a step-up action of the charge pump circuit. When the step-up ratio of the charge pump circuit is 1, the control unit turns on only the second oscillator to perform the time measurement for setting up the step-up ratio based on the second periodic signal.