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:
Aug. 31, 2021
Filed:
May. 23, 2018
Tsuyoshi Ueno, Miyagi, JP;
Yuuki Oka, Miyagi, JP;
Tetsuya Satoh, Miyagi, JP;
Seiya Abe, Fukuoka, JP;
Tsuyoshi Ueno, Miyagi, JP;
Yuuki Oka, Miyagi, JP;
Tetsuya Satoh, Miyagi, JP;
Seiya Abe, Fukuoka, JP;
RICOH COMPANY, LTD., Tokyo, JP;
KYUSHU INSTITUTE OF TECHNOLOGY, Fukuoka, JP;
Abstract
A drive circuitincludes a power source; current control units-to-configured to control the amount of currents supplied to a light emitting element in accordance with a pulse modulation signal; and a calculation unitconfigured to change a duty ratio of a pulse modulation signal. The current control units-to-include a first switching elementconfigured to be switched on/off in accordance with a pulse modulation signal; and a second switching elementconfigured to be switched on/off in accordance with an inversion signal of the pulse modulation signal input to the first switching element; and an inductor. The first switching elementand the inductorare serially connected between the power source and the light emitting element. The second switching elementis connected between groundand a contact pointof the first switching elementand the inductor. The two or more current control units-to-are connected in parallel.