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:
May. 30, 2000
Filed:
Feb. 02, 1998
Srinivasan Venkatraman, Bangalore, IN;
Richard C Pierson, Dallas, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A capacitor current sensing circuitry (100) for sensing the current through a bandpass capacitor (20) of a first biquad stage (80) and generating an output current in response. The capacitor current sensing circuitry (100) includes a differential input circuit comprising a transistor (123) and a transistor (124), a fixed current source (130), a variable current source (120), a variable current, source (122), an input current sink (126), a differential output circuit comprising a transistor (132) and a transistor (134), and a programmable output current sink (138). The differential input circuit receives an input sense voltage and generates a first input current, a second input current, a first output voltage, and a second output voltage in response. The fixed current source (130) generates a current that is used to provide a first current component to the first input current and a first current component to the second input current. The variable current source (120) and the variable current source (122) generate a second component of the first input current and the second input current, respectively. The input current sink (126) receives the first input current and the second input current. The transistor (132) receives the first output voltage and generates a first output current in response, while the transistor (134) receives the second output voltage and generates a second output current in response. The programmable output current sink (138) receives the first output current and the second output current.