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US 7,567,122 B2Granted
Variable gain amplifiers systems and methods
AssigneeSkyworks Solutions, Inc.
InventorTirdad Sowlati
Life of this patent
Estimating the term…
Abstract
A system for controlling gain in a polar loop is disclosed. Embodiments of the invention provide for a substantially constant gain tolerant of changes in supply voltage, ambient temperature, and/or manufacturing process.
Claims20
A method of providing direct current (DC) gain control voltages that operate in opposing manner, the method comprising:
- receiving at a first difference amplifier coupled to a variable gain amplifier:
- a first reference voltage, the first reference voltage corresponding to a summation of a DC shifted voltage and an emitter common mode voltage (ECMV), the ECMV derived from the variable gain amplifier;
- a first control terminal voltage;
- and
- a second control terminal voltage, the first and second control terminal voltage derived from a differential control voltage;
- receiving at a second difference amplifier coupled to the variable gain amplifier a second reference voltage, the first control terminal voltage, and the second control terminal voltage, the second reference voltage corresponding to a summation of a DC shifted voltage and a collector common mode voltage (CCMV), the CCMV derived from the variable gain amplifier;
- at the first difference amplifier, adding the first reference voltage to the second control terminal voltage to provide a first sum, and subtracting from the first sum the first control terminal voltage to provide a first DC gain control voltage;
- at the second difference amplifier, adding the second reference voltage to the first control terminal voltage to provide a second sum, and subtracting from the second sum the second control terminal voltage to provide a second DC gain control voltage that operates in opposing manner to the first DC gain control voltage;
- and
- providing the first DC gain control voltage and the second DC gain control voltage to the variable gain amplifier.
7 more elements
A system for providing direct current (DC) gain control voltages that operate in opposing manner, the system comprising:
- a variable gain amplifier;
- a first difference amplifier coupled to the variable gain amplifier, the first difference amplifier having three inputs configured to receive a first reference voltage, a first control terminal voltage, and a second control terminal voltage, respectively, the first reference voltage corresponding to a summation of a DC shifted voltage and an emitter common mode voltage (ECMV), the ECMV derived from the variable gain amplifier, the first and second control terminal voltage derived from a differential control voltage, wherein the first difference amplifier is configured to add the first reference voltage to the second control terminal voltage to provide a first sum, and subtract from the first sum the first control terminal voltage to provide a first DC gain control voltage to the variable gain amplifier;
- and
- a second difference amplifier coupled to the variable gain amplifier, the second difference amplifier having three inputs configured to receive a second reference voltage, the first control terminal voltage, and the second control terminal voltage, the second reference voltage corresponding to a summation of a DC shifted voltage and a collector common mode voltage (CCMV), the CCMV derived from the variable gain amplifier, wherein the second difference amplifier is configured to add the second reference voltage to the first control terminal voltage to provide a second sum, and subtract from the second sum the second control terminal voltage to provide a second DC gain control voltage that operates in opposing manner to the first DC gain control voltage, the second DC gain control voltage provided to the variable gain amplifier.
1 more element
Dependencies are inferred from the claim text.