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US 6,888,406 B2Granted
Highly linear variable gain amplifier
AssigneeMicrotune (Texas), L.P.
InventorsKirk B. Ashby, Oliver I. Werther
Life of this patent
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Abstract
Disclosed are systems and methods which provide very linear amplification of signals using a linearized transconductance circuit. A transconductance amplifier configuration is shown which provides highly linearized operation utilizing a Darlington pair feedback circuit. Also shown are gain control configurations in which current steering circuitry is adapted to operate in its most linear region.
Claims37
A highly linear variable gain amplifier system comprising:
- a fine gain selection circuit, wherein said fine gain selection circuit provides highly linear operation throughout a predetermined dynamic range;
- and
- a coarse gain selection circuit, wherein said coarse gain selection circuit provides a coarse gain adjustment corresponding to said predetermined dynamic range, wherein said coarse gain selection circuit comprises a plurality of selectable gain stages, wherein each said gain stage of said plurality of selectable gain stages comprises a current mirror circuit.
A system for providing linear amplification of signals, said system comprising:
- a transconductance amplifier;
- and
- a variable gain circuit coupled to an output of said transconductance amplifier, wherein said variable gain circuit includes a fine gain control portion and a coarse gain control portion, wherein said coarse gain control portion of said variable gain circuit comprises a plurality of current mirrors coupled to said output of said transconductance amplifier, and wherein said fine gain control portion of said variable gain circuit comprises a plurality of current steer circuits.
A highly linear variable gain amplifier system comprising:
- a fine gain selection circuit, wherein said fine gain selection circuit provides highly linear operation throughout a predetermined dynamic range;
- and
- a coarse gain selection circuit, wherein said coarse gain selection circuit provides a coarse gain adjustment corresponding to said predetermined dynamic range, wherein said coarse gain selection circuit comprises a plurality of selectable gain stages, wherein said coarse gain selection circuit provides binary coarse gain increments.
A highly linear variable gain amplifier system comprising:
- a fine gain selection circuit, wherein said fine gain selection circuit provides highly linear operation throughout a predetermined dynamic range;
- a coarse gain selection circuit, wherein said coarse gain selection circuit provides a coarse gain adjustment corresponding to said predetermined dynamic range;
- and
- selection circuitry for selecting a desired level of gain provided by said coarse gain selection circuit.
1 more element
A system for providing linear amplification of signals, said system comprising:
- a transconductance amplifier;
- and
- a variable gain circuit coupled to an output of said transconductance amplifier, wherein said variable gain circuit includes a fine gain control portion and a coarse gain control portion, wherein said variable gain circuit further includes a coarse gain selection portion, and wherein said coarse gain selection portion comprises a switch for enabling a gain stage of said coarse gain control portion.
A highly linear variable gain amplifier system comprising:
- a fine gain selection circuit, wherein said fine gain selection circuit provides highly linear operation throughout a predetermined dynamic range;
- a coarse gain selection circuit, wherein said coarse gain selection circuit provides a coarse gain adjustment corresponding to said predetermined dynamic range;
- and
- a transconductance amplifier, wherein an output of said transconductance amplifier is provided to said coarse gain selection circuit and said fine gain selection circuit to thereby provide a variable gain amplifier configuration, wherein said transconductance amplifier comprises a feedback loop providing feedback of signals between two sets of differential pair transistors, wherein said feedback loop comprises a Darlington pair of transistors.
1 more element
A system for providing linear amplification of signals, said system comprising:
- a transconductance amplifier;
- and
- a variable gain circuit coupled to an output of said transconductance amplifier, wherein said variable gain circuit includes a fine gain control portion and a coarse gain control portion, wherein said coarse gain control portion of said variable gain circuit comprises a plurality of current mirrors coupled to said output of said transconductance amplifier, and wherein said plurality of current mirrors are adapted to provide gain in predetermined increments.
A system for providing linear amplification of signals, said system comprising:
- a transconductance amplifier;
- and
- a variable gain circuit coupled to an output of said transconductance amplifier, wherein said variable gain circuit includes a fine gain control portion and a coarse gain control portion, wherein said variable gain circuit further includes a coarse gain selection portion, and wherein said coarse gain selection portion comprises a current steer circuit for switchably selecting an output of a gain stage of said coarse gain control portion.
A system for providing linear amplification of signals, said system comprising:
- a transconductance amplifier, wherein said transconductance amplifier includes a feedback circuit having a buffer transistor providing buffering with respect to a feedback loop transistor;
- and
- a variable gain circuit coupled to an output of said transconductance amplifier, wherein said variable gain circuit includes a fine gain control portion and a coarse gain control portion, wherein said coarse gain control portion of said variable gain circuit comprises a plurality of current mirrors coupled to said output of said transconductance amplifier, wherein said plurality of current mirrors are adapted to provide gain in predetermined increments.
A system for providing linear amplification of signals, said system comprising:
- a transconductance amplifier, wherein said transconductance amplifier includes a feedback circuit having a buffer transistor providing buffering with respect to a feedback loop transistor;
- and
- a variable gain circuit coupled to an output of said transconductance amplifier, wherein said variable gain circuit includes a fine gain control portion and a coarse gain control portion, wherein said fine gain control portion provides continuous gain adjustment and said coarse gain control portion provides gain control in discrete steps.
A method for providing highly linear variable gain amplification of a signal, said method comprising:
- adapting a transconductance amplifier for linear operation;
- providing coarse gain selection, wherein said coarse gain selection provides coarse gain adjustments corresponding to a predetermined increments;
- and
- providing fine gain adjustment, wherein said fine gain adjustment provides highly linear operation throughout a predetermined dynamic range, wherein said predetermined dynamic range corresponds to said predetermined increments.
1 more element
Dependencies are inferred from the claim text.