Power amplifier

Abstract

Embodiments of the present invention comprise methods and devices for amplifying a signal by amplifying a first signal and by then amplifying a second signal only if the first signal exceeds a predetermined threshold. The first and second amplified signals are then combined, and the combination is fed back to a signal source and used to control the values of the first and second signal. The combination is further transmitted to a load. In the preferred embodiment, the first amplified signal is transmitted through an impedance inverter before it is combined with the second amplified signal.

1 . An amplifier comprising: 
 a primary amplifier having an input terminal and an output terminal;    an auxiliary amplifier having an input terminal and an output terminal, the output terminal of the auxiliary amplifier in electrical communication with the output terminal of the primary amplifier; and    a signal source in electrical communication with the input terminal of the primary amplifier and the input terminal of the auxiliary amplifier and in electrical communication with the output terminal of the auxiliary amplifier and the output terminal of the primary amplifier;    wherein the signal source controls the input signals of the primary amplifier and the auxiliary amplifier in response to output signals produced at the output terminal of the auxiliary amplifier and the output terminal of the primary amplifier.    
     
     
         2 . The amplifier of  claim 1  wherein an impedance inverter connects the output terminal of the primary amplifier and the output terminal of the auxiliary amplifier.  
     
     
         3 . The amplifier of  claim 1  wherein a phase shifter connects the signal source and the auxiliary amplifier input terminal.  
     
     
         4 . The amplifier of  claim 1  wherein the input terminal of the primary amplifier and the input terminal of the auxiliary amplifier are in electrical communication with a first output terminal of the signal source.  
     
     
         5 . The amplifier of  claim 1  wherein the input terminal of the primary amplifier and the input terminal of the auxiliary amplifier are in electrical communication with a first output terminal of the signal source and a second output terminal of the signal source, respectively.  
     
     
         6 . The amplifier of  claim 1  wherein the primary amplifier has a control input terminal, the signal source has a control output terminal and the control input terminal of the primary amplifier is in electrical communication with the control output terminal of the signal source.  
     
     
         7 . The amplifier of  claim 1  wherein the auxiliary amplifier has a control input terminal, the signal source has a control output terminal and the control input terminal of the auxiliary amplifier is in electrical communication with the control output terminal of the signal source.  
     
     
         8 . The amplifier of  claim 1  wherein the signal source controls the output of the primary amplifier in response to voltage detected at the output terminals of the primary amplifier and the auxiliary amplifier.  
     
     
         9 . The amplifier of  claim 1  wherein the signal source controls the output of the auxiliary amplifier in response to voltage detected at the output terminals of the primary amplifier and the auxiliary amplifier.  
     
     
         10 . The amplifier of  claim 1  further comprising a load having an input terminal, wherein the input terminal of the load is in electrical communication with the output terminal of the primary amplifier, the output terminal of auxiliary amplifier, and the signal source.  
     
     
         11 . The amplifier of  claim 1  further comprising a voltage source having an output terminal, and a resistor having an input terminal and an output terminal, wherein the output terminal of the voltage source is in electrical communication with the input terminal of the resistor, and wherein the output terminal of the resistor is in electrical communication with the primary amplifier, and wherein the signal source detects the voltage across the resistor.  
     
     
         12 . The amplifier of  claim 1  further comprising a voltage source having an output terminal, and a resistor having an input terminal and an output terminal, wherein the output terminal of the voltage source is in electrical communication with the input terminal of the resistor, and wherein the output terminal of the resistor is in electrical communication with the auxiliary amplifier, and wherein the signal source detects the voltage across the resistor.  
     
     
         13 . The amplifier of  claim 2  wherein the impedance inverter is a lumped impedance element.  
     
     
         14 . The amplifier of  claim 2  wherein the impedance inverter is a quarter-wave transmission line.  
     
     
         15 . The amplifier of  claim 3  wherein the phase shifter is a lumped impedance element.  
     
     
         16 . The amplifier of  claim 3  wherein the phase shifter is a quarter-wave transmission line.  
     
     
         17 . The amplifier of  claim 1  wherein the primary amplifier is a class F amplifier and the auxiliary amplifier is an inverse class F amplifier.  
     
     
         18 . A method for amplifying a signal comprising the steps of: 
 (a) amplifying a first signal to produce a first amplified signal;    (b) amplifying a second signal to produce a second amplified signal, only if the first amplified signal exceeds a threshold value;    (c) combining the first amplified signal with the second amplified signal to produce an amplified output signal; and    (d) modifying the first signal and the second signal in response to the amplified output signal.    
     
     
         19 . The method of  claim 18  further comprising the step of transmitting the first amplified signal through an impedance inverter before the first amplified signal is combined with the second amplified signal.  
     
     
         20 . The method of  claim 18  further comprising the step of modifying the first signal in response to the voltage of the first amplified signal.  
     
     
         21 . The method of  claim 18  further comprising the step of modifying the second signal in response to the voltage of the second amplified signal.  
     
     
         22 . The method of  claim 18  further comprising the step of modifying the first and second signals in response to the output signal.  
     
     
         23 . The method of  claim 18  further comprising the step of transmitting the amplified output signal through a load.  
     
     
         24 . The method of  claim 18 , wherein amplifying the first signal comprises controlling the first amplifier operating point in response to the amplified output signal.  
     
     
         25 . The method of  claim 18  wherein amplifying the second signal comprises controlling the second amplifier operating point in response to the amplified output signal.  
     
     
         26 . The method of  claim 18  wherein the first signal and the second signal are the same signal.  
     
     
         27 . The method of  claim 26  wherein the second signal is transmitted through a phase shifter before being amplified.  
     
     
         28 . The method of  claim 19  wherein the impedance inverter is a lumped impedance element.  
     
     
         29 . The method of  claim 19  wherein the impedance inverter is a quarter-wave transmission line.  
     
     
         30 . The method of  claim 27  wherein the phase shifter is a lumped impedance element.  
     
     
         31 . The method of  claim 27  wherein the phase shifter is a quarter-wave transmission line.  
     
     
         32 . An amplifier comprising: 
 (a) a means for amplifying a first signal to produce a first amplified signal;    (b) a means for amplifying a second signal to produce a second amplified signal, only if the first amplified signal exceeds a threshold value;    (c) a means for combining the first amplified signal with the second amplified signal to produce an amplified output signal;    (d) a means for modifying the first signal and the second signal in response to the amplified output signal.    
     
     
         33 . The amplifier of  claim 32  further comprising a means for transmitting the first amplified signal through an impedance inverter before the first amplified signal is combined with the second amplified signal.  
     
     
         34 . The amplifier of  claim 32  further comprising a means for controlling the first signal using the output signal.  
     
     
         35 . The amplifier of  claim 32  further comprising a means for controlling the second signal using the output signal.  
     
     
         36 . The amplifier of  claim 32  further comprising a means for transmitting the amplified output signal through a load  
     
     
         37 . The amplifier of  claim 32  further comprising a means for controlling the voltage of the first signal amplification using the amplified output signal.  
     
     
         38 . The amplifier of  claim 32  further comprising a means for controlling the voltage of the second signal amplification using the amplified output signal.  
     
     
         39 . The amplifier of  claim 32  wherein the first signal and the second signal are the same signal.  
     
     
         40 . The amplifier of  claim 32  wherein the second signal is transmitted through a phase shifter before being amplified.  
     
     
         41 . The amplifier of  claim 33  wherein the impedance inverter is a lumped impedance element.  
     
     
         42 . The amplifier of  claim 33  wherein the impedance inverter is a quarter-wave transmission line.  
     
     
         43 . The amplifier of  claim 40  wherein the phase shifter is a lumped impedance element.  
     
     
         44 . The amplifier of  claim 40  wherein the phase shifter is a quarter-wave transmission line.