Method and apparatus providing integrated load matching using adaptive power amplifier compensation
First Claim
1. A power amplifier module operable over a range of output power levels, comprising an output transistor having an input coupled to an input node of the power amplifier module and an output coupled to an output node of the power amplifier module, the power amplifier module further comprising circuitry for automatically compensating a load line of the output transistor for impedance variations appearing at the output node, the circuitry comprising detection circuitry for generating a first detection signal having a value that is indicative of the current flowing through the output transistor and a second detection signal having a value that is indicative of the voltage appearing at the output of the output transistor, and further comprising compensation circuitry for controlling the generation of a plurality of power amplifier bias current and bias voltage signals to have values that are a function of the values of the first and second detection signals, and the current output power level of the power amplifier module.
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Abstract
An RF power amplifier module can be used without a matching device between the power amplifier module and an antenna. The power amplifier module is constructed and operated to detect, protect and maintain the performance of the power amplifier in the presence of severe VSWR load mismatches, without requiring the use of external circuitry. The RF power amplifier module includes integral detection circuitry for generating a first detection signal having a value that is indicative of the current flowing through an output power transistor and a second detection signal having a value that is indicative the voltage appearing at the output of the output power transistor, as well as integral compensation circuitry for controlling the generation of a plurality of bias current and bias voltage signals to have values that are a function of the values of the first and second detection signals, as well as the current output power level of the RF power amplifier module. Also included is an integral impedance matching circuit, coupled between the output of the output transistor and the output node, that provides a variable impedance that is selectively controlled by an output signal from the compensation circuitry.
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Citations
25 Claims
- 1. A power amplifier module operable over a range of output power levels, comprising an output transistor having an input coupled to an input node of the power amplifier module and an output coupled to an output node of the power amplifier module, the power amplifier module further comprising circuitry for automatically compensating a load line of the output transistor for impedance variations appearing at the output node, the circuitry comprising detection circuitry for generating a first detection signal having a value that is indicative of the current flowing through the output transistor and a second detection signal having a value that is indicative of the voltage appearing at the output of the output transistor, and further comprising compensation circuitry for controlling the generation of a plurality of power amplifier bias current and bias voltage signals to have values that are a function of the values of the first and second detection signals, and the current output power level of the power amplifier module.
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9. A method to operate a power amplifier module over a range of output power levels, comprising:
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generating a first detection signal having a value that is indicative of current flowing through an output transistor and a second detection signal having a value that is indicative of a voltage appearing at an output of the output transistor; and
automatically compensating a load line of the output transistor for impedance variations appearing at an output node of the power amplifier module by controlling the generation of a plurality of power amplifier bias current and bias voltage signals to have values that are a function of the values of the first and second detection signals, and the current output power level of the power amplifier module. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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- 17. A radio frequency (RF) power amplifier module operable over a range of output power levels, comprising an output transistor having an input coupled to an input node of the power amplifier module for receiving a wideband code division, multiple access signal to be transmitted from an antenna and an output coupled to an output node of the RF power amplifier module, the RF power amplifier module further comprising circuitry for automatically compensating the output transistor for impedance variations appearing at the output node due at least in part to a change in an RF propagation environment of the antenna, the circuitry comprising detection circuitry for generating a first detection signal having a value that is indicative of the current flowing through the output transistor and a second detection signal having a value that is indicative the voltage appearing at the output of the output transistor, and further comprising compensation circuitry for controlling the generation of a plurality of power amplifier bias current and bias voltage signals to have values that are a function of the values of the first and second detection signals, respectively, and the value of a signal that is indicative of a current output power level of the RF power amplifier module, further comprising an impedance matching circuit coupled between the output of the output transistor and the output node, the impedance matching circuit presenting a variable impedance that is controlled by an output signal from the compensation circuitry, where the output signal from the compensation circuitry is generated to have a value that is a function of the value of the first detection signal and the value of the signal that is indicative of the current output power level of the RF power amplifier module.
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20. A radio frequency (RF) power amplifier contained within a package, the RF power amplifier being operable over a range of output power levels specified by a value of a power control signal that is one of applied to a first input of the package and generated internally to the package, the RF power amplifier comprising at least one output transistor having an input coupled to second input of the package for receiving an input RF signal and an output coupled to an output of the package for outputting an amplified RF signal, the RF power amplifier further comprising circuitry integrated with the at least one output transistor for automatically compensating the RF amplifier for impedance variations appearing at the first output, the circuitry comprising detection circuitry for generating detection signals indicative of current flowing through the at least one output transistor and of a voltage appearing at the output of the at least one output transistor, and further comprising load line compensation circuitry responsive to the detection signals and to the power control signal for maintaining a desired output linearity of the amplified RF signal.
- 21. A mobile radiocommunication terminal comprising an antenna and, coupled to the antenna, a radio frequency (RF) power amplifier module that is operable over a range of output power levels, said RF power amplifier module comprising at least one output transistor having an input coupled to an input node of the power amplifier module for receiving a signal to be transmitted from the antenna and an output coupled to an output node of the RF power amplifier module, the RF power amplifier module further comprising circuitry for automatic compensation of the output transistor for impedance variations appearing at the output node due at least in part to variations in an environment of the antenna, the automatic compensation circuitry comprising detection circuitry for generating a first detection signal having a value that is indicative of the current flowing through the at least one output transistor and a second detection signal having a value that is indicative the voltage appearing at the output of the at least one output transistor, and further comprising bias control circuitry for controlling the generation of a plurality of power amplifier bias current and bias voltage signals to have values that are a function of the values of the first and second detection signals, respectively, and also the value of a signal that is indicative of a current output power level of the RF power amplifier module, further comprising an impedance matching circuit coupled between the output of the at least one output transistor and the output node, the impedance matching circuit presenting a variable impedance that is controlled by an output signal from the automatic compensation circuitry, where the output signal from the automatic compensation circuitry is generated to have a value that is a function of the value of the first detection signal and the value of the signal that is indicative of the current output power level of the RF power amplifier module.
Specification