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. 12, 1996
Filed:
Dec. 09, 1994
Michinao Kawano, Yokohama, JP;
Setsuo Misaizu, Yokohama, JP;
Tomoko Anzai, Yokohama, JP;
Takashi Tsuda, Kawasaki, JP;
Fujitsu Limited, Kanagawa, JP;
Abstract
An automatic temperature control circuit of a laser diode solves a problem that a temperature control becomes unstable when switching to heat or cool the laser diode. In the circuit, a peltier element changes the temperature of the laser diode by heating or cooling, a temperature detecting section detects the temperature of the laser diode and outputs the corresponding detected voltage, an error amplifying section outputs an error voltage by comparing the detected outputted voltage with a fixed value, a peltier current control section controls the direction of a driving current flowing to the peltier element in correspondence with an error voltage outputted from the error amplifying section. In addition, there is provided a circuit which feed-backs a voltage corresponding to the driving current flowing to the peltier element to an input side of the error amplifying section and adds it to the detected voltage outputted from the temperature detecting section.