Stacked power amplifier power control
First Claim
1. A circuital arrangement comprising:
- a stack of a plurality of transistors arranged in a cascode configuration, comprising;
(i) an input transistor adapted to receive an input radio frequency (RF) signal; and
(ii) one or more cascoded transistors, the one or more cascoded transistors comprising an output transistor adapted to output, at an adjustable output power, an output RF signal based on the input RF signal, anda compensation circuit adapted to generate a compensation voltage that is a function of a supply voltage to the stack that is a varying supply voltage,wherein;
a variation of the adjustable output power with respect to the varying supply voltage is compensated for by varying at least one gate voltage of the one or more cascoded transistors of the stack according to a variable voltage level of the varying supply voltage, andthe at least one gate voltage is a combination of the compensation voltage and a nominal gate voltage that is configured to provide a nominal output power of the adjustable output power.
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Accused Products
Abstract
Systems, methods and apparatus for efficient power control and/or compensation with respect to a varying supply voltage of an RF amplifier for amplification of a constant envelope RF signal are described. A reduction in a size of a pass device of an LDO regulator is obtained by removing the pass device of the LDO regulator from a main current conduction path of the RF amplifier. Power control and/or compensation is provided by varying one or more gate voltages to cascoded transistors of a transistor stack of the RF amplifier according to a power control voltage. Various configurations for controlling the gate voltages are presented by way of a smaller size LDO regulator or by completely removing the LDO regulator. In a case where a supply voltage to the transistor stack varies, such as in a case of a battery, a compensation circuit is used to adjust the power control voltage in view of a variation of the supply voltage, and therefore null a corresponding drift/variation in output power of the RF amplifier.
29 Citations
21 Claims
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1. A circuital arrangement comprising:
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a stack of a plurality of transistors arranged in a cascode configuration, comprising; (i) an input transistor adapted to receive an input radio frequency (RF) signal; and (ii) one or more cascoded transistors, the one or more cascoded transistors comprising an output transistor adapted to output, at an adjustable output power, an output RF signal based on the input RF signal, and a compensation circuit adapted to generate a compensation voltage that is a function of a supply voltage to the stack that is a varying supply voltage, wherein; a variation of the adjustable output power with respect to the varying supply voltage is compensated for by varying at least one gate voltage of the one or more cascoded transistors of the stack according to a variable voltage level of the varying supply voltage, and the at least one gate voltage is a combination of the compensation voltage and a nominal gate voltage that is configured to provide a nominal output power of the adjustable output power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for compensating a variation of an output power of an amplifier arrangement operating from a varying supply voltage, the method comprising:
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providing a stack of a plurality of transistors arranged in a cascode configuration, comprising an input transistor and one or more cascoded transistors, the one or more cascoded transistors comprising an output transistor; supplying the varying supply voltage across the stack; providing gate voltages to the one or more cascoded transistors configured to provide a nominal output power at the output transistor; inputting a constant envelope radio frequency (RF) signal to the input transistor; based on the inputting, obtaining an amplified RF signal at the output transistor having an output power that varies with respect to the nominal output power as a function of the varying supply voltage; generating a compensation voltage that is a function of the varying supply voltage; combining the compensation voltage with at least one gate voltage of the gate voltages to the one or more cascoded transistors; and based on the combining, compensating a variation of the output power of the amplified RF signal so that the nominal output power is maintained. - View Dependent Claims (21)
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Specification