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.

Date of Patent:
Feb. 18, 1997

Filed:

Jan. 28, 1993
Applicant:
Inventors:

Yuji Miyaki, Kawasaki, JP;

Michikazu Shima, Kawasaki, JP;

Assignee:

Fujitsu Limited, Kanagawa, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01S / ;
U.S. Cl.
CPC ...
372 38 ; 372 36 ; 372 28 ; 372 26 ;
Abstract

A drive circuit drives an electronic device that converts electric power into light or heat energy. The drive circuit has a switch connected to the electronic device in series, and a control circuit for providing, in response to an input control signal, a pulse modulation signal for controlling the switch. The frequency of the pulse modulation signal is higher than the response frequency of the electronic device. Alternatively, the drive circuit may have first to fourth switches disposed on both sides of the electronic device, for passing a current in different directions through the electronic device, and a control circuit for controlling the switches to change the direction and magnitude of the average of the current flowing through the electronic device in response to an input control signal.


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