Shared linearity maintenance in power amplifiers

1. A circuit; comprising:

a power amplifier including

a current sensor configured to sense the current drawn by the power amplifier and provide a first sensor output signal dependent upon current consumption when the current exceeds a predetermined current threshold;

a voltage sensor configured to sense an output power of the power amplifier and provide a second sensor output signal when the RF voltage during up ramp falls below a predetermined threshold voltage; and

a summing circuit configured to receive the first and second sensor output signals and provide a feedback signal including a combination of a power dependent contribution and either of a voltage dependent contribution or a current dependent contribution.

2. The circuit of claim 1 , wherein an automatic power controller is coupled to the power amplifier using a serial peripheral interface.

3. The circuit of claim 1 , wherein the feedback signal is received by a front-end circuit including an automatic power controller.

4. The system of claim 2 , wherein the predetermined current threshold is set via the serial peripheral interface.

5. The system of claim 2 , wherein the predetermined threshold voltage is set via the serial peripheral interface.

6. The system of claim 1 , further comprising an antenna coupled to the power amplifier.

7. A method comprising:

providing a first feedback signal, the first feedback signal providing a signal having a magnitude dependent upon a load voltage when the load voltage falls below a predetermined voltage threshold;

providing a second feedback signal, the second feedback signal having a magnitude dependent upon a current when the current drawn exceeds a predetermined current threshold; and

adding either one of the first feedback signal and second feedback signal with a power dependent contribution signal and providing the combined signal as a hybrid feedback.

8. The method of claim 7 , wherein the predetermined current threshold and the predetermined voltage threshold is set via a serial peripheral interface.

9. The method of claim 8 , wherein the predetermined current threshold and the predetermined voltage threshold are set using an automatic power controller.

10. A method, comprising:

sensing a dc current;

sensing an output voltage;

comparing the dc current to a predetermined threshold current;

comparing the output voltage to a predetermined minimum output voltage;

providing a first feedback signal if the dc current exceeds the current threshold, the amplitude of the first feedback signal determined by the amount that the dc current exceeds the threshold current;

providing a second feedback signal if the dc current is less than the current threshold and if the output voltage is less than a predetermined minimum output voltage, the magnitude of the second feedback signal determined by the amount that the predetermined minimum output voltage exceeds the output voltage;

adding either one of the first feedback signal and second feedback signal with a power dependent contribution signal; and

generating a hybrid feedback input signal based on the power dependent contribution and either one of the first feedback signal and the second feedback signal.

11. The method of claim 10 , wherein the predetermined current threshold and the predetermined voltage threshold is set via a serial peripheral interface.

12. The method of claim 11 , wherein the predetermined current threshold and the predetermined voltage threshold is set using an automatic power controller.