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:
Sep. 09, 2003
Filed:
Jun. 28, 1999
Katsuji Kaminishi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
An optical semiconductor diode driver circuit, which is stably operable even with the supply of a source voltage slightly higher than the forward operation voltage of an optical semiconductor diode to be driven and can output switch current and voltage sufficient for driving the optical semiconductor diode, includes a pre-driver circuit operating as a limiting amplifier, and an output circuit responsive to a pulse-shaped voltage output from the pre-driver circuit and outputting a drive pulse current to the optical semiconductor diode as an external load. The output circuit is basically a type of the emitter-coupled amplifier which has either a differential configuration or a similar one to a Schmitt circuit and whose common-emitter loads are composed of a resistor and a variable constant current source to determine a amplitude of the output current pulse with small rise and fall times. Since a variable constant current source is added, the circuit alleviates influences from variations of the impedance of the load and the operating environment without any degradation of high frequency characteristics.