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:
Aug. 07, 2007
Filed:
Sep. 19, 2005
Hon K. Chiu, Hayward, CA (US);
Hon K. Chiu, Hayward, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A circuit for a digitally operating linear-in-decibels attenuator circuit controlled using an analog control signal. The attenuator circuit includes a resistor ladder, digitally controlled switches, and a flash analog-to-digital converter. The resistive ladder includes resistances coupled in series between an input and output electrode. The resistive ladder also includes shunt resistances, each of which is coupled to a corresponding series resistance and to a corresponding digitally controlled switch that is controlled by a corresponding digital control signal. Each of the switches include a pole electrode coupled to a corresponding shunt resistance and to the input electrode, and a throw electrode coupled to the corresponding shunt resistance and to the common node for attenuating voltage from an input signal. The flash analog-to-digital converter is controlled by an analog control signal and outputs digital control signals in a thermometer code for controlling the digitally controlled switches.