Multimode RF amplifier system

1. A multimode radio frequency (RF) amplifier system comprising:

a first semiconductor die;

a first RF amplifier formed on the first semiconductor die and including an auxiliary circuit formed on the same first semiconductor die as the first RF amplifier, wherein the first RF amplifier is configured to:

receive a first modulated RF input signal;

generate a first modulated RF output signal based on the first modulated RF input signal; and

provide the first modulated RF output signal for transmission; and

a second RF amplifier coupled to the auxiliary circuit, wherein the second RF amplifier is configured to receive a second RF input signal and generate a second RF output signal based on the second RF input signal, wherein:

operation of the first RF amplifier and the auxiliary circuit are mutually exclusive such that:

when the first RF amplifier is ON, the auxiliary circuit is OFF, and

when the auxiliary circuit is ON, the first RF amplifier is OFF;

the second RF amplifier is electromagnetically isolated from the first RF amplifier; and

the auxiliary circuit is configured to provide a utility to the second RF amplifier.

2. The multimode RF amplifier system of claim 1 wherein the utility provided to the second RF amplifier enables the second RF amplifier to generate the second RF output signal.

3. The multimode RF amplifier system of claim 1 wherein:

the first RF amplifier includes a transmit enable signal having a transmit enabled state and a transmit disabled state; and

the auxiliary circuit is further configured to provide the utility to the second RF amplifier only while the transmit enable signal is set to the transmit disabled state.

4. The multimode RF amplifier system of claim 1 wherein the utility provided by the auxiliary circuit to the second RF amplifier comprises:

generating a supply voltage; and

providing the supply voltage to the second RF amplifier.

5. The multimode RF amplifier system of claim 4 further comprising a power source voltage input configured to receive a power source voltage; and

wherein the auxiliary circuit is further configured to boost the power source voltage to generate the supply voltage.

6. The multimode RF amplifier system of claim 4 wherein the auxiliary circuit comprises:

a power source voltage input configured to receive a power source voltage; and

a switching network including a first flying capacitor interface configured to communicatively couple the switching network to a first terminal of a first flying capacitor and a second terminal of the first flying capacitor; and

wherein the auxiliary circuit is further configured to generate the supply voltage as a function of a first flying capacitor voltage developed across the first flying capacitor interface, the switching network, and the power source voltage.

7. The multimode RF amplifier system of claim 6 wherein the switching network further comprises a second flying capacitor interface configured to communicatively couple the switching network to a first terminal of a second flying capacitor and a second terminal of the second flying capacitor; and

wherein the auxiliary circuit is further configured to generate the supply voltage as a function of the first flying capacitor voltage developed across the first flying capacitor interface, a second flying capacitor voltage developed across the second flying capacitor interface, the switching network, and the power source voltage.

8. The multimode RF amplifier system of claim 4 wherein:

the supply voltage is a modulated supply voltage; and

the auxiliary circuit further comprises:

a power source voltage input configured to receive a power source voltage; and

a target supply voltage input configured to receive a target supply voltage that substantially tracks an envelope of a modulated RF input signal provided to the second RF amplifier; and

wherein the auxiliary circuit is further configured to generate the modulated supply voltage as a function of the target supply voltage.

9. The multimode RF amplifier system of claim 8 wherein the target supply voltage is for envelope tracking at least one of a 3G signal and a 4G Long Term Evolution (LTE) signal.

10. The multimode RF amplifier system of claim 4 wherein the auxiliary circuit is further configured to operate as a bang-bang power supply converter configured to generate the supply voltage.

11. The multimode RF amplifier system of claim 4 wherein the auxiliary circuit is further configured to generate the supply voltage to substantially track an envelope of a second modulated RF input signal to be transmitted by the second RF amplifier.

12. The multimode RF amplifier system of claim 4 wherein the auxiliary circuit is configured to operate as a boost power supply converter to generate the supply voltage.

13. The multimode RF amplifier system of claim 4 wherein the auxiliary circuit is further configured to operate as a buck-boost power supply converter to generate the supply voltage.

14. The multimode RF amplifier system of claim 13 wherein the auxiliary circuit is further configured to generate the supply voltage to substantially track an envelope of a modulated RF input signal to be transmitted by the second RF amplifier.

15. The multimode RF amplifier system of claim 1 wherein the auxiliary circuit further comprises an auxiliary signal interface configured to:

interface with the second RF amplifier; and

provide the utility to enable the second RF amplifier via the auxiliary signal interface.

16. The multimode RF amplifier system of claim 15 wherein:

the utility provided to the second RF amplifier that is not used by the first RF amplifier is a first utility;

the auxiliary circuit further includes a second utility; and

the auxiliary circuit further comprises control circuitry and the auxiliary signal interface is configured to provide the second utility, wherein:

the auxiliary signal interface is configured to interface with the second RF amplifier; and

the control circuitry includes a control interface configured to interface with a master device, and configured to govern the second RF amplifier via the auxiliary signal interface.

17. The multimode RF amplifier system of claim 16 wherein the control interface includes a control bus interface configured to communicate with the master device.

18. The multimode RF amplifier system of claim 17 wherein the control bus interface includes a serial bus interface.

19. The multimode RF amplifier system of claim 17 wherein the control bus interface includes a parallel bus interface.

20. The multimode RF amplifier system of claim 16 wherein the control circuitry is further configured to govern an operation of the first RF amplifier.

21. The multimode RF amplifier system of claim 16 wherein the control interface comprises a mobile industry processor interface (MIPI) RF front-end (RFFE) control interface.

22. A radio frequency (RF) amplification device comprising:

a semiconductor die;

an RF power converter formed on the semiconductor die, wherein the RF power converter is configured to generate a regulated supply voltage from a power source voltage and a modulated supply voltage from the power source voltage;

a first RF amplification circuit formed on the semiconductor die, wherein the first RF amplification circuit is configured to amplify a first RF signal using the regulated supply voltage from the RF power converter; and

a second RF amplification circuit electromagnetically isolated from the RF power converter, wherein the second RF amplification circuit is configured to amplify a second RF signal using the modulated supply voltage from the RF power converter,

wherein operation of the first amplification circuit and the RF power converter are mutually exclusive such that:

when the first RF amplification circuit is ON, the RF power converter is OFF, and

when the RF power converter is ON, the first RF amplification circuit is OFF.

23. The RF amplification device of claim 22 , wherein the second RF amplification circuit is coupled to the RF power converter so as to receive the modulated supply voltage.

24. The RF amplification device of claim 22 further comprising:

a second semiconductor die, wherein the second RF amplification circuit is formed on the second semiconductor die so as to be electromagnetically isolated from the RF power converter.

25. The RF amplification device of claim 22 wherein the RF power converter comprises:

a voltage regulation circuit configured to generate the regulated supply voltage from the power source voltage, wherein the voltage regulation circuit is formed on the semiconductor die; and

an RF switching converter configured to generate the modulated supply voltage from the power source voltage, wherein the RF switching converter is formed on the semiconductor die.

26. The RF amplification device of claim 25 further comprising a power controller formed on the semiconductor die, wherein the power controller is configured to:

enable the voltage regulation circuit;

disable the voltage regulation circuit;

enable the RF switching converter; and

disable the RF switching converter.

27. The RF amplification device of claim 22 wherein the second RF amplification circuit is formed on the semiconductor die such that the second RF amplification circuit is electromagnetically isolated from the RF power converter.

28. The RF amplification device of claim 27 wherein the RF power converter comprises an RF switching converter configured to generate the modulated supply voltage from the power source voltage, and the semiconductor die comprises:

a first active region comprising the RF power converter, wherein the first active region is formed on the semiconductor die;

a second active region comprising the second RF amplification circuit, wherein the second active region is formed on the semiconductor die such that the first active region and the second active region are electromagnetically isolated.

29. The RF amplification device of claim 28 wherein the second active region is discontinuous with the first active region and the second active region is separated from the first active region so as to electromagnetically isolate the second active region from the first active region.

30. The RF amplification device of claim 29 wherein the first active region further comprises the first RF amplification circuit.

31. The RF amplification device of claim 28 wherein the first active region and the second active region are each formed with a Bipolar Complementary Metal-Oxide Silicon (Bi-CMOS) technology.

32. The RF amplification device of claim 27 wherein the semiconductor die is a Silicon Germanium-type semiconductor die.

33. The multimode RF amplifier system of claim 1 further comprising a second semiconductor die, wherein the second RF amplifier is formed on the second semiconductor die.