RF amplifier bias control method and apparatus
First Claim
1. A bias control circuit for use with an RF amplifier having an input, an output, a supply voltage and a plurality of operating performance characteristics responsive to a quiescent operating point established by the RF amplifier bias current, said circuit comprising:
- means, coupled to the RF amplifier, for detecting a DC current drawn by the RF amplifier from the supply voltage; and
means, coupled to the detecting means, and the RF amplifier, for adjusting the RF amplifier bias current as a function of the detected DC current, to control the RF amplifier'"'"'s quiescent operating point and thereby optimize the RF amplifier'"'"'s operation for selected operating performance characteristics.
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Accused Products
Abstract
A bias control circuit (200) for use with an RF amplifier (202) comprises a detector (R1) coupled to the RF amplifier (202) for detecting a DC current provided to the amplifier (202) from supply voltage (VCC). Thereafter, an adjustment circuit (206-210), coupled to the detector (R1) and the RF amplifier (202) adjusts the amplifier'"'"'s bias voltage (V bias) as a function of the current draw in order to control the RF amplifier'"'"'s quiescent operating point (bias current) and thereby optimize the RF amplifier'"'"'s operation for selected operating performance characteristics like gain performance, intermodulation performance, and efficiency.
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Citations
9 Claims
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1. A bias control circuit for use with an RF amplifier having an input, an output, a supply voltage and a plurality of operating performance characteristics responsive to a quiescent operating point established by the RF amplifier bias current, said circuit comprising:
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means, coupled to the RF amplifier, for detecting a DC current drawn by the RF amplifier from the supply voltage; and means, coupled to the detecting means, and the RF amplifier, for adjusting the RF amplifier bias current as a function of the detected DC current, to control the RF amplifier'"'"'s quiescent operating point and thereby optimize the RF amplifier'"'"'s operation for selected operating performance characteristics. - View Dependent Claims (2, 3, 4, 5)
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6. In an RF amplifier having an input, an output, a supply voltage and a plurality of operating performance characteristics, responsive to a quiescent operating point established by the RF amplifier'"'"'s bias current, a method for controlling said bias current comprising the steps of:
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detecting a DC current level drawn by the RF amplifier by the supply voltage; and adjusting the RF amplifier bias current as a function of the detected DC current, to control the RF amplifier'"'"'s quiescent operating point. - View Dependent Claims (7, 8)
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9. A bias control circuit for use with an RF amplifier having an input, an output, a supply voltage and a plurality of operating performance characteristics responsive to a quiescent operating point established by the RF amplifier bias current, said circuit comprising:
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a detector coupled to the RF amplifier, for detecting a DC current drawn by said amplifier by the supply voltage and including a resistor coupled between the supply voltage and the RF amplifier, and a differential amplifier having first and second inputs coupled to terminals of said resistor to sense said current and provide an output signal; and means, responsive to the output signal for varying the RF amplifier bias current.
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Specification