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:
Mar. 04, 2003
Filed:
Aug. 18, 2000
Applicant:
Inventor:
Toyoki Taguchi, Yokohama, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01S 3/00 ;
U.S. Cl.
CPC ...
H01S 3/00 ;
Abstract
In a laser drive circuit for use in an optical disc recording and reproducing apparatus, a P-channel MOS transistor acting as a drive current source generates a drive current I depending on a setting current Ic. A P-channel MOS transistor acting as a current switch supplies the drive current I to a semiconductor laser, in response to a drive pulse signal CP. An OP amplifier controls a setting current Ic depending on a monitor current Im and a setting voltage Vc. A capacitor removes noise generated by the transistor acting as a current switch and superposed on the drive current I .