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. 03, 1998
Filed:
Dec. 15, 1995
Yukio Aizawa, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A control circuit of a light-emitting device comprises a negative-feedback loop including a photodetector and a sample and hold circuit. The photodetector monitors an optical signal emitted by the light-emitting device and the sample and hold circuit generates a control signal supplied to a light-emitting device driver. The sample and hold circuit performs the sampling of a monitored signal each time the light-emitting device emits light and holds the sampled monitored signal. The voltage held in the sample and hold circuit is output as the control signal the light-emitting device driver. The light-emitting device driver drives the light-emitting device to switch on and off according to the input digital data with the output light intensity of the light-emitting device controlled by the control signal so as to be kept at a constant level.