Amplifier output power limiting circuitry

A system, having an input terminal and an output terminal, comprising:

• an amplifier connected to the input terminal for receiving an input signal at the input terminal and for producing an output signal at the output terminal, the amplifier having a linear operating region where an output signal produced by the amplifier at the output terminal has a power level increasing proportionally with the increasing input signal power level and a compression operating region where the output signal power produced by the amplifier has a compression power level, Pout_cmpr, invariant with the input signal power level when the power of the input signal is above a predetermined input power level;
• a DC current limiting circuit, coupled between a DC power supply and a bias terminal of the amplifier, for biasing the amplifier to limit the output power at the output terminal of the system to a level below the compression power level Pout_cmpr while enabling the output power of the system to vary proportionally with input signal power when the input signal power level is below the predetermined power level;
• and
• wherein the DC current limiting circuit:
• allows the amplifier to draw current from the DC power supply through the DC current limiting circuit having a first, substantially constant, level for a first range of input signal power level;
• allows the current drawn from the DC power supply through the DC current limiting circuit to increase from the first substantially constant level to a second, higher, level for a range of input power level greater than the first range of input signal power level;
• and, inhibits the current being drawn from the DC power supply through the DC bias limiting circuit current from increasing above the second level for a third range of input signal power level greater than the second range of input signal power level.

A circuit, comprising

• an amplifier having:
• an input terminal for receiving an input signal, an output terminal for producing an output signal;
• and a current supply terminal for receiving a bias current, the amplifier having a linear operating region and a compression region, the operating region of the amplifier being a function of the input signal and DC bias, the amplifier amplifying the input signal to produce the output signal;
• a non-linear circuit coupled between a DC voltage supply and the current supply terminal, the DC voltage supply providing a current to the amplifier through the non-linear circuit, the current producing a voltage (ΔV) across the non-linear circuit, such voltage (ΔV) being a function of the input signal, the non-linear circuit operating in an ohmic region when (ΔV) has a first level, operating in a saturation region when (ΔV) has a second level greater than then first level, or operating in a transition region between the ohmic region and the saturation region when (ΔV) has a third level greater than the first level and lower than the second level, the non-linear circuit operating in the ohmic region when the input signal operates the amplifier in the linear region of the amplifier and the non-linear circuit operating in the saturation region when the input signal operates the amplifier in the in the compression region of the amplifier.