Controlled power boost for envelope tracker

1. A system comprising:

a voltage output;

a signal input;

a boost input; and

a power converter in communication with the voltage output, the boost input, and the signal input, the power converter operable to:

receive an input voltage signal on the signal input, the input voltage signal having a voltage envelope;

generate a voltage supply signal on the voltage output that approximates the voltage envelope; and

respond to a boost signal present on the boost input by activating a supplemental power source to facilitate generation of the voltage supply signal; and

a detector configured to:

determine an upcoming peak in the input voltage signal; and

output the boost signal on the boost input in response to the upcoming peak.

2. The system of claim 1 , where the power converter is operable to disable the supplemental power source except when the boost signal is present.

3. The system of claim 1 , where the voltage output comprises a power amplifier voltage supply output.

4. The system of claim 1 , where the boost input comprises a dedicated input pin.

5. The system of claim 1 , where the power converter is further operable to receive the boost signal prior to receiving a signal peak in the input voltage signal.

6. The system of claim 1 , where the supplemental power source comprises a boost converter.

7. The system of claim 1 , where the supplemental power source comprises a first supplemental power converter and a second supplemental power converter; and where the power converter is operable to respond to the boost signal by selecting between the first and second supplemental power converters to facilitate generation of the supply voltage.

8. The system of claim 1 , where the supplemental power source is configured to boost a signal tracking capability for the voltage supply signal.

9. A method comprising:

generating, with a power supply, an output power supply voltage that tracks an input signal envelope; and

obtaining a sample of the input signal envelope;

storing the sample in a signal sample memory;

performing, at controller circuitry, an analysis of the sample to determine an upcoming peak in the input signal envelope; and

responsive to the upcoming peak, boosting a signal tracking capability of the power supply.

10. The method of claim 9 , where boosting comprises selectively activating a supplemental power source that boosts the signal tracking capability.

11. The method of claim 9 , where boosting the signal tracking capability comprises boosting peak tracking capability of the power supply.

12. The method of claim 9 , further comprising:

receiving a boost configuration input; and

determining whether to boost the signal tracking capability depending on the boost configuration input.

13. The method of claim 12 , where receiving the boost configuration input comprises receiving a boost signal from a baseband controller.

14. The method of claim 9 , where boosting the signal tracking capability of the power supply comprises selecting between a first supplemental power converter and a second supplemental power converter to facilitate generation of the supply voltage.

15. A system comprising:

a power amplifier powered by a voltage supply signal and configured to amplify an input signal for transmission over an antenna;

an envelope-tracking (ET) converter configured to:

receive an input voltage signal having a voltage envelope; and

generate an approximation of the voltage envelope as the voltage supply signal;

a digital detector configured to:

detect an upcoming peak in the input voltage signal; and

output a boost signal in response to the upcoming peak;

a boost converter configured to:

receive the boost signal; and

in response to the boost signal, provide supplemental power to facilitate generating the approximation of the voltage envelope.

16. The system of claim 15 , where the boost converter comprises a dedicated boost control pin configured to receive the boost signal from the detector.

17. The system of claim 16 , where the boost converter is configured to remain inactive except when the boost signal is present.

18. The system of claim 15 , where the boost converter comprises first and second independently selectable power supplies with different power output capacities.

19. The system of claim 15 , further comprising:

a signal sample memory in communication with the detector, the signal sample memory operable to store signal sample data that the detector analyzes to detect the upcoming peak.

20. The system of claim 19 , where the detector comprises:

a baseband controller operable to provide the input voltage signal to the ET converter based on the signal sample data.