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. 31, 1989
Filed:
Feb. 29, 1988
Yusuf A Haque, San Jose, CA (US);
Maxim Integrated Products, Sunnyvale, CA (US);
Abstract
The invention relates to a self-biasing, programmable, universal active filter having an input section which includes an operational amplifier. The amplifier has one output and two input terminals. A first capacitor has one of its terminals coupled to a first of the input terminals of the amplifier and the other terminal serving as an input node to the filter. The second capacitor is coupled between the same input terminal and the output terminal. The filter has a bandpass section having an output and an input coupled to the output terminal of the amplifier. The filter has a low pass section having an output and an input coupled to the output of the bandpass section. The filter has a third capacitor coupled between the first input terminal of the amplifier and the output of the bandpass section. Finally, the filter uses a pair of switched capacitors under clock control, one in parallel with the first capacitor and the other in parallel with the second capacitor, whereby DC current can flow from the input terminal of the filter to first input terminal of the amplifier, and from the same one input terminal of the amplifier to the output terminal of the amplifier during at least a portion of the clock cycle.