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. 20, 1998
Filed:
Jan. 27, 1997
Michael K Poimboeuf, San Mateo, CA (US);
Jeff DiNapoli, San Carlos, CA (US);
Gerald L Brainard, San Jose, CA (US);
Silicon Graphics, Inc., Mountain View, CA (US);
Abstract
The present invention comprises an active shunt filter for filtering a power supply for noise sensitive devices. The active shunt filter includes a transistor and an op amp. A first resistor is coupled between the emitter of the transistor and a first power supply. A second resistor is coupled between the collector of the transistor and a ground. A third resistor is coupled between the base of the transistor and the output of the op amp. The output of the op amp controls the impedance of the transistor. The op amp is coupled to receive power from a second power supply. The negative input of the op amp is coupled to the emitter. The positive input of the op amp is coupled to the first power supply via a fourth resistor. A fifth resistor couples the positive input of the op amp to ground. A capacitor is also coupled between the positive input of the op amp and ground. The op amp controls a shunt current flowing from the first power supply to ground via the transistor to produce a filtered power output for a noise sensitive device at the emitter of the transistor.