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:
Nov. 05, 2002
Filed:
Sep. 04, 2001
Andrew T. K. Tang, San Jose, CA (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
A ping-pong amplifier employs auto-zeroing and chopping to simultaneously achieve low offset voltage and low frequency noise, as well as low energy at the chopping frequency. The ping-pong amplifier includes respective nulling amplifiers for each of its gain amplifiers, which auto-zero each gain amplifier. In addition, switches are included which allow the inputs and outputs of the active gain amplifier to be chopped. Thus, while one gain amplifier is being auto-zeroed, the other gain amplifier amplifies the input signal and its inputs and outputs are chopped. One of the described embodiments includes circuitry which reduces switching transients that might otherwise appear in the amplifier's output by ensuring that the common-mode output voltage of each gain amplifier is kept equal to a common-mode reference voltage.