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.

Date of Patent:
Sep. 01, 1992

Filed:

May. 21, 1990
Applicant:
Inventor:

John G Banaska, Brunswick, OH (US);

Assignee:

Keithley Instruments, Inc., Cleveland, OH (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03K / ; G01R / ;
U.S. Cl.
CPC ...
307242 ; 3072964 ; 3072965 ; 307571 ; 324 / ; 324115 ;
Abstract

A range selecting impedance is switched into or out of a parallel range-selecting network by connecting the impedance across the network through an n-channel and a p-channel FET connected in parallel output configuration. The n-channel FET does the switching if the drains are negative with respect to the sources. The p-channel FET does the switching if the drains are positive with respect to the sources. Each FET is controlled by a gate drive whose output waveform is varied to select the rate at which the FETs switch. In cases of several different switched range impedances, the FETs are used to switch the smallest impedance into the network, another range impedance is selected, and then the FETs used to switch the smallest impedance out of the network. In this way, fast glitch-free range switching is achieved.


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