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:
Jan. 11, 2000
Filed:
Feb. 24, 1999
Masashi Tachigori, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
Output current of light receiving element Dph is converted into a voltage by a core amplification section, and the voltage output is extracted as an amplification output through an outputting circuit section. The output voltage is fed back to the base of transistor T2 of a differential circuit of the core amplification section, by which it is compared with base reference voltage Vref of transistor T1. When the input current is low, the gain of the core amplification section is dominated by the product of the current flowing through transistor T2 and resistor R4, but when the input current is high, the gain is dominated by the product of current flowing through transistor T1 and resistor R3. Consequently, if resistor R3 is set lower than resistor R4, then when the input current is high, the gain margin indicating a degree of stability of the feedback circuit can be made large, and this stabilizes operation of the front-end amplification circuit.