Temperature and process compensating circuit and controller for an RF power amplifier
First Claim
1. An amplifying apparatus comprising:
- an RF gain stage for providing an amplified RF signal at an output terminal thereof;
means for generating a differential signal indicative of a fluctuation in temperature or process of said RF gain stage from an ambient value; and
a control circuit comprising an operational amplifier responsive to said differential signal and to a variable input control signal for providing a control signal to said RF gain stage to compensate said RF gain stage for said temperature or process fluctuation to maintain a substantially constant power output at said output terminal.
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Accused Products
Abstract
A radio frequency (RF) power amplifier circuit comprising an RF gain stage formed on an integrated circuit (IC) chip comprising at least one field effect transistor configured for amplifying an RF signal to provide an amplified RF signal to an antenna at a given RF power level; a compensation circuit formed on the IC chip for generating a first voltage VS+ and a second voltage VS− at respective first and second output terminals, the voltage difference therebetween corresponding to a level of temperature or process fluctuation from a given level associated with the RF gain stage; and a control circuit comprising an operational amplifier coupled to the output terminals of the compensation circuit for receiving the first and second voltages VS+, VS− and outputting a control signal to the gate of the at least one FET of the RF gain stage to compensate the RF gain stage for the fluctuation, whereby a substantially constant power output to the antenna is maintained.
219 Citations
27 Claims
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1. An amplifying apparatus comprising:
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an RF gain stage for providing an amplified RF signal at an output terminal thereof;
means for generating a differential signal indicative of a fluctuation in temperature or process of said RF gain stage from an ambient value; and
a control circuit comprising an operational amplifier responsive to said differential signal and to a variable input control signal for providing a control signal to said RF gain stage to compensate said RF gain stage for said temperature or process fluctuation to maintain a substantially constant power output at said output terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
a first resistor coupled between a source electrode of said FET and a reference potential, said FET having a gate electrode coupled to said source electrode, and a drain electrode coupled to a supply voltage, a second resistor having a first terminal coupled to said drain electrode and a second terminal coupled to a first terminal of a third resistor, said third resistor having a second terminal coupled to said reference potential, wherein the voltage across said first resistor corresponds to said VS+ signal, and wherein the voltage drop across said third resistor corresponds to said VS−
signal.
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8. The apparatus according to claim 7, wherein said first and third resistors are of equal resistance values.
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9. The apparatus according to claim 1, wherein said RF gain stage includes a plurality of cascaded MESFETs for amplifying said RF signal, and wherein said means for generating a differential signal includes a MESFET coupled to a voltage divider network for generating said differential signal.
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10. A radio frequency (RF) power amplifier circuit comprising:
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an RF gain stage formed on an integrated circuit (IC) chip comprising at least one field effect transistor configured for amplifying an RF signal to provide an amplified RF signal to an antenna at a given RF power level;
a compensation circuit formed on said IC chip for generating a first voltage VS+ and a second voltage VS−
at respective first and second output terminals thereof, the voltage difference therebetween corresponding to a level of temperature or process fluctuation associated with said RF gain stage from a given level; and
a control circuit comprising an operational amplifier coupled to the first and second output terminals of said compensation circuit for receiving said first and second voltages VS+, VS−
and outputting a control signal to the gate of said at least one FET of said RF gain stage to compensate said RF gain stage for said fluctuation, whereby a substantially constant power output to said antenna is maintained.- View Dependent Claims (11, 12, 13, 14, 15)
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16. An RF power amplifier circuit comprising:
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a plurality of FET amplifiers coupled together in a cascaded configuration for amplifying an RF signal to provide an amplified RF signal at an output terminal and at a given power;
a sensing circuit comprising a FET amplifier having temperature characteristics similar to those of said plurality of FET amplifiers, said sensing circuit positioned adjacent said plurality such that said sensing circuit is affected by temperature fluctuations in said plurality of FET amplifiers, said sensing circuit having first and second output terminals for outputting first and second voltage signals respectively which correspond to a differential voltage indicative of the sensed difference in temperature from a given level of said plurality of FET amplifiers; and
a control circuit comprising an operational amplifier for receiving said first and second differential voltage signals and responsive to a variable input control voltage for providing an output control signal to at least one gate electrode of said plurality of FETs to cause a change in output characteristics of said plurality to compensate for said sensed temperature fluctuation. - View Dependent Claims (17, 18, 19)
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20. A power amplifier circuit comprising:
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an RF gain stage formed on an integrated circuit (IC) for providing an amplified RF signal at an output terminal thereof;
a compensation circuit formed on said IC chip for generating a first voltage and a second voltage at respective first and second output terminals thereof, the voltage difference therebetween corresponding to a level of fluctuation associated with said RF gain stage from a given level; and
a control circuit comprising an operational amplifier coupled to the first and second output terminals of said compensation circuit for receiving said first and second voltages and outputting a control signal to said RF gain stage to compensate said RF gain stage for said fluctuation.
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21. A compensation circuit for use in a power amplifier comprising:
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a sensor circuit including a transistor for producing a first voltage signal and a second voltage signal at output terminals thereof, said first and second voltage signals corresponding to a differential voltage therebetween indicative of a fluctuation in temperature in an amplification stage of said power amplifier; and
a control circuit comprising an operational amplifier responsive to said first and second voltage signals and to an at least one input control signal for providing a control signal to said amplification stage to compensate said amplification stage for said temperature fluctuation. - View Dependent Claims (22)
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23. An amplifying apparatus comprising:
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an RF gain stage for providing an amplified RF signal at an output terminal thereof;
a sensor circuit for generating a differential voltage signal indicative of a fluctuation in temperature of said RF gain stage from an ambient value; and
a control circuit comprising an operational amplifier responsive to said differential voltage signal and to an at least one input control signal for providing a control signal to said RF gain stage to compensate said RF gain stage for said temperature fluctuation to maintain a substantially constant power output at said output terminal. - View Dependent Claims (24, 25, 26, 27)
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Specification