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:
Oct. 04, 2005
Filed:
May. 18, 2001
Richard L. Gower, San Jose, CA (US);
Eric G. Hoffman, Fremont, CA (US);
Bhupendra K. Ahuja, Fremont, CA (US);
J. Antonio Salcedo, Livermore, CA (US);
Richard L. Gower, San Jose, CA (US);
Eric G. Hoffman, Fremont, CA (US);
Bhupendra K. Ahuja, Fremont, CA (US);
J. Antonio Salcedo, Livermore, CA (US);
Exar Corporation, Fremont, CA (US);
Abstract
A programmable gain amplifier having three separately programmable amplifiers. A programmable transconductance amplifier is followed by a programmable transimpedance amplifier, then a programmable switched capacitor amplifier. In one embodiment, this programmable gain amplifier is implemented in an analog front-end (AFE) circuit. One AFE embodiment provides a coarse pre-gain offset a black reference level sampler, and a fine post-gain offset in the programmable switched capacitor amplifier. In one embodiment, an ADC reference is sampled, and is subtracted directly from the video signal in the switched capacitor amplifier so that the zero level of the video signal is made to correspond to the zero level of the ADC. In another embodiment, a piece-wise linear approximation of an exponential gain function is implemented by programming the transconductance and transimpedance amplifiers to provide exponential jumps in gain, while the switched capacitor amplifier is programmed to interpolate as needed between the exponential gain levels.