Power amplifier control technique for enhanced efficiency
First Claim
1. A system comprising:
- a) power amplifier circuitry comprising;
i) at least one input amplifier stage adapted to operate in saturation and amplify a radio frequency input signal based on a variable supply voltage to provide an amplified radio frequency signal; and
ii) a final amplifier stage adapted to receive a fixed supply voltage and adapted to amplify the amplified radio frequency signal to provide an output radio frequency signal; and
b) power control circuitry adapted to provide the variable supply voltage based on an adjustable power control signal, thereby controlling an output power of the power amplifier circuitry based on the adjustable power control signal,wherein when the output power is reduced from a first output power level to a second output power level via the adjustable power control signal, the power control circuitry operates to reduce the variable supply voltage and thus the RF power of the amplified radio frequency signal such that the final amplifier stage transitions from a saturation mode to a linear mode thereby increasing a gain of the final amplifier stage.
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Accused Products
Abstract
A power amplifier configuration including power amplifier circuitry and power control circuitry and having improved Power Added Efficiency (PAE) is provided. The power amplifier circuitry includes one or more input amplifier stages in series with a final amplifier stage. The power control circuitry provides a variable supply voltage to the input amplifier stages based on an adjustable power control signal. The final amplifier stage is powered by a fixed supply voltage. In operation, as output power of the power amplifier is reduced from its highest power level, the variable supply voltage is reduced. Accordingly, RF power of an amplified signal provided to the final amplifier stage from the input amplifier stages decreases, and the final amplifier stage transitions from saturation to linear operation, thereby increasing the gain of the final amplifier stage. Thus, a desired output level can be maintained while operating at lower current levels.
94 Citations
33 Claims
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1. A system comprising:
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a) power amplifier circuitry comprising; i) at least one input amplifier stage adapted to operate in saturation and amplify a radio frequency input signal based on a variable supply voltage to provide an amplified radio frequency signal; and ii) a final amplifier stage adapted to receive a fixed supply voltage and adapted to amplify the amplified radio frequency signal to provide an output radio frequency signal; and b) power control circuitry adapted to provide the variable supply voltage based on an adjustable power control signal, thereby controlling an output power of the power amplifier circuitry based on the adjustable power control signal, wherein when the output power is reduced from a first output power level to a second output power level via the adjustable power control signal, the power control circuitry operates to reduce the variable supply voltage and thus the RF power of the amplified radio frequency signal such that the final amplifier stage transitions from a saturation mode to a linear mode thereby increasing a gain of the final amplifier stage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15, 16, 17, 18, 19, 20)
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12. A system comprising:
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power amplifier circuitry comprising; at least one input amplifier stage adapted to operate in saturation and amplify a radio frequency input signal based on a variable supply voltage to provide an amplified radio frequency signal; and a final amplifier stage adapted to receive a fixed supply voltage and adapted to amplify the amplified radio frequency signal to provide an output radio frequency signal; power control circuitry adapted to provide the variable supply voltage based on an adjustable power control signal, thereby controlling an output power of the power amplifier circuitry based on the adjustable power control signal; current detection circuitry adapted to detect a current in the final amplifier stage and provide a signal indicative of the current; error amplification circuitry adapted to provide a control signal based on a comparison of the adjustable power control signal and the signal indicative of the current in the final amplifier stage; and a voltage regulator adapted to provide the variable supply voltage based on the control signal and a source voltage. - View Dependent Claims (13, 14)
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21. A method comprising:
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a) providing at least one input amplifier stage in series with a final amplifier stage for amplifying a radio frequency input signal, the at least one input amplifier stage operating in saturation; b) providing power to the at least one input amplifier stage from a variable supply voltage; c) providing a fixed supply voltage to the final amplifier stage; and d) providing the variable supply voltage responsive to an adjustable power control signal, thereby controlling an output power of the at least one input amplifier stage and the final amplifier stage, wherein when the output power is reduced from a first output power level to a second output power level via the adjustable power control signal, the step of providing the variable supply voltage comprises reducing the variable supply voltage and thus an RF input power at the input of the final amplifier stage such that the final amplifier stage transitions from saturation mode to linear mode thereby increasing a gain of the final amplifier stage. - View Dependent Claims (22, 23, 24, 25, 26, 30, 31, 32, 33)
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27. A method comprising:
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providing at least one input amplifier stage in series with a final amplifier stage for amplifying a radio frequency input signal, the at least one input amplifier stage operating in saturation; providing power to the at least one input amplifier stage from a variable supply voltage; providing a fixed supply voltage to the final amplifier stage; providing the variable supply voltage responsive to an adjustable power control signal, thereby controlling an output power of the at least one input amplifier stage and the final amplifier stage; providing a signal indicative of a current in the final amplifier stage; providing a control signal based on a comparison of the adjustable power control signal and the signal indicative of the current in the final amplifier stage; and providing the variable supply voltage based on the control signal and a source voltage. - View Dependent Claims (28, 29)
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Specification