Power amplifier with variable input voltage source
First Claim
Patent Images
1. A power amplifier circuit comprising:
- an amplifier arranged to receive an input signal and to provide an amplified output signal, the amplifier including a direct current voltage input, the direct current voltage input being coupled to a direct current voltage source;
a detector coupled to the input signal, the detector providing a characteristic of the input signal, the amplifier comprising a power amplifier stage and an intermediate amplifier stage, the detector coupled to an input of the intermediate amplifier stage; and
the direct current voltage source responsive to the characteristic for providing a step-wise variable voltage to the amplifier.
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Abstract
A power amplifier circuit (10) utilizes a step-wise variable voltage source (22) to improve amplifier (14) operating efficiency. In one preferred embodiment, an input signal to the step-wise variable voltage source is obtained by observing an operating characteristic of the amplifier. In an alternate preferred embodiment of the present invention, a characteristic of the input signal driving the amplifier stage is used to form an input signal to the step-wise variable input voltage source.
45 Citations
15 Claims
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1. A power amplifier circuit comprising:
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an amplifier arranged to receive an input signal and to provide an amplified output signal, the amplifier including a direct current voltage input, the direct current voltage input being coupled to a direct current voltage source; a detector coupled to the input signal, the detector providing a characteristic of the input signal, the amplifier comprising a power amplifier stage and an intermediate amplifier stage, the detector coupled to an input of the intermediate amplifier stage; and the direct current voltage source responsive to the characteristic for providing a step-wise variable voltage to the amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A power amplifier circuit comprising:
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a power amplifier circuit comprising a power amplifier stage and an intermediate amplifier stage and including a radio frequency signal input, an amplified signal output and a direct current voltage input; a signal characteristic detector coupled to an input of the intermediate amplifier stage, the signal characteristic detector adapted to detect a characteristic of the radio frequency signal input and to produce a voltage control signal; and a step-wise variable voltage source responsive to the voltage control signal for providing a step-wise variable voltage to the direct current voltage input. - View Dependent Claims (14, 15)
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Specification