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:
May. 13, 2008
Filed:
Nov. 17, 2006
Toshio Nishida, Kyoto, JP;
Sho Maruyama, Kanagawa, JP;
Toshio Nishida, Kyoto, JP;
Sho Maruyama, Kanagawa, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
A semiconductor laser driving circuit has a circuit protection function at low temperature and includes a voltage current converter that converts an input voltage Vin, which is determined according to a desired light brightness of the semiconductor laser to be driven, into a current. A current limiter limits an output current of the voltage current converter to a specified current value or less. An output amplifier amplifies the output current of the voltage current converter and supplies the amplified current as a drive current to the semiconductor laser. A temperature detection circuit detects a low temperature state and, in the low temperature state, decreases the specified current value of the current limiter.