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. 11, 2001
Filed:
Feb. 03, 1999
Cheng-chung Shih, Fremont, CA (US);
Jiann-chyi Shieh, San Jose, CA (US);
Broadcom Corporation, Irvine, CA (US);
Abstract
An amplifier circuit is responsive to an input data signal which is substantially DC balanced. The amplifier circuit is operative to generate an amplified data signal, and includes: a limiting amplifier responsive to the input data signal and to an error correcting signal, the limiting amplifier being operative to generate the amplified data signal; a feed back circuit responsive to a signal proportional to the amplified data signal, the feed back circuit being operative to generate the error correcting signal. The feed back circuit includes: a low pass filter responsive to the signal proportional to the amplified data signal, and operative to generate a filtered signal; and an error amplifier responsive to the filtered signal, and operative to provide the error correcting signal to the limiting amplifier; whereby offset voltage caused by process characteristics of the limiting amplifier, and temperature variations in the limiting amplifier are canceled by the error correcting feedback signal. The limiting amplifier further includes: a first amplifying stage operative to provide a first stage amplified signal; a second amplifying stage responsive to the first stage amplified signal, and operative to provide a second stage amplified signal; and a third amplifying stage responsive to the second stage amplified signal, and operative to generate the amplified data signal. The low pass filter of the feedback circuit generates the filtered signal in response to the second stage amplified signal; and the error correcting signal is provided to the second amplifying stage of the limiting amplifier.