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. 09, 1990
Filed:
Sep. 26, 1989
Gerald Miller, Hudson, NH (US);
Christopher O'Connor, Methuen, MA (US);
Analog Devices, Inc., , US;
Abstract
An auto-zeroing sample-hold amplifier capable of tracking an input voltage and, when designated, sampling and accurately holding an input voltage with no gain or offset errors includes input and output buffers with complementary, equal-magnitude offsets for minimizing offset voltage errors. An input voltage is sampled across a primary hold capacitor as well as a secondary hold capacitor [at the amplifier output to] in a sample mode. In a hold mode, the capacitors, in conjunction with the buffers and a transconductance amplifier, form a negative feedback loop around the transconductance amplifier to hold the sampled voltage and reduced voltage excursions at the output of the sample-hold amplifier. A special cancellation switch and capacitor are included for differentially cancelling voltage errors caused by switch charge feed-through onto the primary hold capacitor.