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. 20, 1983

Filed:

Jan. 21, 1982
Applicant:
Inventors:

Thomas Hornak, Portola Valley, CA (US);

Gary L Baldwin, Palo Alto, CA (US);

Assignee:

Hewlett-Packard Company, Palo Alto, CA (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03K / ;
U.S. Cl.
CPC ...
3403 / ; 3403 / ;
Abstract

A bit cell is presented which can provide a small weighted current without loss of switching speed. The bit cell contains a switch which is responsive to an applied control signal to direct the weighted current to an output or to divert it away from the output. Supplementary currents are supplied to the switch to provide sufficient current to the switch to charge and discharge parasitic capacitances of the switch within the switching time of the control voltage. The supplementary currents maximize switching speed at a given power dissipation and produce a constant offset current at the switch output. A D/A converter is presented which utilizes a plurality of such bit cells to maximize the speed of D/A conversion. The offset currents are eliminated from the converter output so that the output current is proportional to the digital input.


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