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:
Apr. 19, 2016
Filed:
Mar. 22, 2012
Masaki Noda, Tokyo, JP;
Masaki Noda, Tokyo, JP;
Mitsubishi Electric Corporation, Tokyo, JP;
Abstract
A photodiode converts an optical signal output from a laser diode to a current signal, and a current-to-voltage conversion circuit converts the current signal to a voltage signal. A comparison amplifier compares the voltage signal with a reference voltage to control the current flowing from a variable current source and increases or decreases a bias current for driving the laser diode. The current-to-voltage conversion circuit comprises a resistor and a variable current source that are connected in parallel. Therefore, it is possible to change the bias current without changing the resistance value of the resistor and to avoid limiting the dynamic range of the optical signal that is output. In addition, since the resistance value of the resistor does not change, the loop gain does not change, thereby stabilizing the control operation.