SOLID-STATE RF POWER AMPLIFIER FOR RADIO TRANSMITTERS
First Claim
1. An RF power amplifier, comprising:
- a first field effect transistor;
having a first gate, a first source, and a first drain,having an output power rating of at least 200 watts, andoperating with a drain-to-source voltage that is greater than 50 VDC;
a second field effect transistor;
having a second gate, a second source, and a second drain,having an output power rating of at least 200 watts, andoperating with a drain-to-source voltage that is greater than 50 VDC;
wherein said transistors are configured as a push-pull amplifier;
an RF signal input;
an input transformer connected to the RF signal input, the input transformer having respective balanced outputs connected to the first gate and the second gate;
a broadband output transformer having a first balanced input connected to the first drain, and a second balanced input connected to the second drain, wherein the broadband output transformer has an input to output impedance ratio of 1;
4, and further wherein at least some flux cancellation occurs within the broadband output transformer; and
temperature compensating bias circuitry for providing a temperature compensated bias voltage to the first field effect transistor and the second field effect transistor for decreasing the bias voltage of the first field effect transistor and the second field effect transistor as transistor temperature increases, the temperature compensating bias circuitry comprising;
a temperature sensor generating a temperature signal;
a first amplifier having an output providing a first temperature dependent voltage based on the temperature signal;
a second amplifier having an output providing a second temperature dependent voltage based on the temperature signal, wherein the first temperature dependent voltage and the second temperature dependent voltage change at substantially the same rate in response to the temperature signal; and
a potentiometer connected to the output of the first amplifier and the output of the second amplifier such that a voltage across the potentiometer remains substantially constant when the first temperature dependent voltage and the second temperature dependent voltage change; and
a bias output connected to at least one of the first field effect transistor and the second field effect transistor and supplying the temperature compensated bias voltage to the at least one of the first field effect transistor and the second field effect transistor.
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Accused Products
Abstract
An RF power amplifier includes a push-pull amplifier having field effect transistors. Temperature compensating bias circuitry provides a temperature compensated bias voltage to the transistors for decreasing the bias voltage thereof as temperature increases. The temperature compensating bias circuitry includes a temperature sensor generating a temperature signal. A first amplifier provides a first temperature dependent voltage based on the temperature signal. A second amplifier provides a second temperature dependent voltage based on the temperature signal. The first and second temperature dependent voltages change at substantially the same rate in response to the temperature signal. A potentiometer receives the first and second temperature dependent voltages such that a voltage across the potentiometer remains substantially constant when the first and second temperature dependent voltages change. An output of the bias circuitry is connected to at least one of the transistors and supplies the temperature compensated bias voltage to the at least one of the transistors.
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Citations
30 Claims
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1. An RF power amplifier, comprising:
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a first field effect transistor; having a first gate, a first source, and a first drain, having an output power rating of at least 200 watts, and operating with a drain-to-source voltage that is greater than 50 VDC; a second field effect transistor; having a second gate, a second source, and a second drain, having an output power rating of at least 200 watts, and operating with a drain-to-source voltage that is greater than 50 VDC; wherein said transistors are configured as a push-pull amplifier; an RF signal input; an input transformer connected to the RF signal input, the input transformer having respective balanced outputs connected to the first gate and the second gate; a broadband output transformer having a first balanced input connected to the first drain, and a second balanced input connected to the second drain, wherein the broadband output transformer has an input to output impedance ratio of 1;
4, and further wherein at least some flux cancellation occurs within the broadband output transformer; andtemperature compensating bias circuitry for providing a temperature compensated bias voltage to the first field effect transistor and the second field effect transistor for decreasing the bias voltage of the first field effect transistor and the second field effect transistor as transistor temperature increases, the temperature compensating bias circuitry comprising; a temperature sensor generating a temperature signal; a first amplifier having an output providing a first temperature dependent voltage based on the temperature signal; a second amplifier having an output providing a second temperature dependent voltage based on the temperature signal, wherein the first temperature dependent voltage and the second temperature dependent voltage change at substantially the same rate in response to the temperature signal; and a potentiometer connected to the output of the first amplifier and the output of the second amplifier such that a voltage across the potentiometer remains substantially constant when the first temperature dependent voltage and the second temperature dependent voltage change; and a bias output connected to at least one of the first field effect transistor and the second field effect transistor and supplying the temperature compensated bias voltage to the at least one of the first field effect transistor and the second field effect transistor. - View Dependent Claims (2, 3)
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4. An RF power amplifier, comprising:
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a first plurality of field effect transistors having directly interconnected drains and respective output power ratings of at least 100 watts; a second plurality of field effect transistors having directly interconnected drains and respective output power ratings of at least 100 watts; wherein said transistors operate with a drain-to-source voltage that is greater than 50 VDC, and wherein the first plurality of field effect transistors and the second plurality of field effect transistors together form a push-pull amplifier having an output power rating of at least 400 watts; an RF signal input; an input transformer connected to the RF signal input, the input transformer having respective balanced outputs connected to gates of the first plurality of field effect transistors and gates of the second plurality of field effect transistors; and a broadband output transformer having a first balanced input connected to the drains of the first plurality of field effect transistors, and a second balanced input connected to the drains of the second plurality of field effect transistors, wherein the broadband output transformer has an input to output impedance ratio of 1;
4, and further wherein at least some flux cancellation occurs within the broadband output transformer; andtemperature compensating bias circuitry for providing a temperature compensated bias voltage to the first plurality of field effect transistors and the second plurality of field effect transistors for decreasing the bias voltage of the first plurality of field effect transistors and the second plurality of field effect transistors as transistor temperature increases, the temperature compensating bias circuitry comprising; a temperature sensor generating a temperature signal; a first amplifier having an output providing a first temperature dependent voltage based on the temperature signal; a second amplifier having an output providing a second temperature dependent voltage based on the temperature signal, wherein the first temperature dependent voltage and the second temperature dependent voltage change at substantially the same rate in response to the temperature signal; and a potentiometer connected to the output of the first amplifier and the output of the second amplifier such that a voltage across the potentiometer remains substantially constant when the first temperature dependent voltage and the second temperature dependent voltage change; and a bias output connected to at least one of the first plurality of field effect transistors and the second plurality of field effect transistors and supplying the temperature compensated bias voltage to the at least one of the first plurality of field effect transistors and the second plurality of field effect transistors. - View Dependent Claims (5, 6)
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7. An RF power amplifier, comprising:
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a push-pull amplifier, the push-pull amplifier comprising a first field effect transistor and a second field effect transistor; and temperature compensating bias circuitry for providing a temperature compensated bias voltage to the first field effect transistor and the second field effect transistor for decreasing the bias voltage of the first field effect transistor and the second field effect transistor as transistor temperature increases, the temperature compensating bias circuitry comprising; a temperature sensor generating a temperature signal; a first amplifier having an output providing a first temperature dependent voltage based on the temperature signal; and a potentiometer connected to the output of the first amplifier such that a voltage across the potentiometer remains substantially constant when the first temperature dependent voltage changes; and a bias output connected to at least one of the first field effect transistor and the second field effect transistor and supplying the temperature compensated bias voltage to the at least one of the first field effect transistor and the second field effect transistor. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An RF power amplifier, comprising:
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a push-pull amplifier, the push-pull amplifier comprising a first field effect transistor having a first drain and a second field effect transistor having a second drain; a broadband output transformer having a first balanced input and a second balanced input; a first DC-blocking transformer connected between the first balanced input and the first drain; and a second DC-blocking transformer connected between the second balanced input and the second drain. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An RF power amplifier, comprising:
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a first amplifier module comprising a first push-pull amplifier including a plurality of field effect transistors and a first output balun transformer, wherein an output impedance of the first amplifier module is 25 ohms; a second amplifier module comprising a second push-pull amplifier including a plurality of field effect transistors and a second output balun transformer, wherein an output impedance of the second amplifier module is 25 ohms; a combiner connected to the first amplifier module and the second amplifier module, the combiner comprising an unbalanced-to-unbalanced output transformer having an input-to-output impedance ratio of 1;
4,wherein the combiner combines an output from the first amplifier module and an output from the second amplifier module into a combined signal, wherein the combined signal is supplied to the unbalanced-to-unbalanced output transformer, and wherein an output impedance of the combiner is 50 ohms. - View Dependent Claims (30)
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Specification