Power amplifying circuit with load adjust for control of adjacent and alternate channel power
First Claim
Patent Images
1. A power amplifying circuit comprising:
- a power amplifier for amplifying an input signal to produce an amplified signal;
a variable impedance network coupled to an output of the power amplifier, the variable impedance network for presenting different impedances to the output of the power amplifier responsive to a load control signal;
a peak-to-average difference detector coupled to an output of the power amplifier, the peak-to-average difference detector to detect a peak level of the amplified signal and an average power of the amplified signal and to provide an indication of a difference between the peak level and the average power; and
a controller coupled to the peak-to-average difference detector and the variable impedance network, the controller for producing the load control signal responsive to the indication of the difference between the peak level and the average power of the amplified signal.
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Abstract
A power amplifying circuit with load adjust for control of adjacent and alternate channel power. A power amplifier amplifies an input signal to produce an amplified signal. A variable impedance network presents different impedances to the output of the power amplifier responsive to a load control signal. A peak-to-average detector provides an indication of a peak-to-average ratio of the amplified signal. A controller coupled to the peak-to-average detector and the variable impedance network produces the load control signal responsive to the indication of the peak-to-average ratio.
192 Citations
21 Claims
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1. A power amplifying circuit comprising:
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a power amplifier for amplifying an input signal to produce an amplified signal; a variable impedance network coupled to an output of the power amplifier, the variable impedance network for presenting different impedances to the output of the power amplifier responsive to a load control signal; a peak-to-average difference detector coupled to an output of the power amplifier, the peak-to-average difference detector to detect a peak level of the amplified signal and an average power of the amplified signal and to provide an indication of a difference between the peak level and the average power; and a controller coupled to the peak-to-average difference detector and the variable impedance network, the controller for producing the load control signal responsive to the indication of the difference between the peak level and the average power of the amplified signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A power amplifying circuit comprising:
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a power amplifier for amplifying an input signal to produce an amplified signal; a variable impedance network coupled to an output of the power amplifier, the variable impedance network for presenting different impedances to the output of the power amplifier responsive to a load control signal; a peak-to-average detector coupled to an output of the power amplifier, the peak-to-average detector to provide an indication of a peak-to-average ratio of the amplified signal; and a controller coupled to the peak-to-average detector and the variable impedance network, the controller for producing the load control signal responsive to the indication of the peak-to-average ratio of the amplified signal. - View Dependent Claims (8, 9, 10, 11)
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12. A transmitter operable in a portable radiotelephone, the transmitter comprising:
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digital baseband circuitry for receiving an information signal and producing a digital stream; transmitter circuitry for converting the digital stream into an radio frequency (RF) input signal; a power amplifying circuit including; a power amplifier for amplifying the RF input signal to produce an amplified signal; a variable impedance network coupled to an output of the power amplifier, the variable impedance network for presenting different impedances to the output of the power amplifier responsive to a load control signal; a digital peak detector coupled to the digital baseband circuitry, the digital peak detector for determining when a peak in the RF input signal is to occur and producing a peak indication signal; a peak-to-average detector coupled to an output of the power amplifier and responsive to the peak indication signal, the peak-to-average detector to provide an indication of a peak-to-average ratio of the amplified signal; and a controller coupled to the peak-to-average detector and the variable impedance network, the controller for producing the load control signal responsive to the indication of the peak-to-average ratio of the amplified signal. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method of amplifying a radio frequency (RF) signal, the method comprising:
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amplifying the RF signal with a power amplifier to produce an amplified signal; detecting a peak-to-average ratio of the amplified signal; producing an indication of the peak-to-average ratio; and changing impedances presented to an output of the power amplifier responsive to the indication of the peak-to-average ratio. - View Dependent Claims (19, 20)
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21. A power amplifying circuit comprising:
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a power amplifier for amplifying an input signal to produce an amplified signal; a variable impedance network coupled to an output of the power amplifier, the variable impedance network for presenting different impedances to the output of the power amplifier responsive to a load control signal; a peak-to-average difference detector coupled to an output of the power amplifier, the peak-to-average difference detector to detect a peak level of the amplified signal and an average power of the amplified signal and to provide an indication of a difference between the peak level and the average power; a controller coupled to the peak-to-average difference detector and the variable impedance network, the controller for producing a digital control signal responsive to the indication of the difference between the peak level and the average power of the amplified signal; and a shift register coupled to the controller and the variable impedance network, the shift register to convert the digital control signal to the load control signal.
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Specification