Amplifier control based on load impedance and methods
View Patent ↗A method of operating an amplifier, for example, in a wireless radio transceiver, including monitoring a characteristic of the amplifier during an operating interval of the amplifier, for example, during a transmission burst, providing an open-loop control signal to the amplifier during a subsequent operating interval of the amplifier wherein the open-loop control signal based on the characteristic monitored during a previous operating interval. In one embodiment, the corrected control signals are stored in a look-up table ( 510 ) that is updated based on the changes in load impedance.
1. A method of operating an amplifier, the method comprising:
monitoring a characteristic of the amplifier during an operating interval of the amplifier;
providing an open-loop control signal to the amplifier during a subsequent operating interval of the amplifier,
the open-loop control signal based on the characteristic monitored during a previous operating interval.
2. The method of claim 1 ,
comparing the characteristic monitored with a reference characteristic;
selecting the open-loop control signal provided to the amplifier during the subsequent operating interval based on the comparison of the characteristic monitored with the reference characteristic.
3. The method of claim 1 ,
monitoring the characteristic of the amplifier includes monitoring the characteristic over multiple operating intervals of the amplifier, and averaging the characteristic monitored,
generating the open-loop control signal based on the average of the characteristic monitored over the multiple operating intervals of the amplifier.
4. The method of claim 1 , monitoring the characteristic of the amplifier includes detecting at least one of an output power of the amplifier, a supply current of the amplifier, and a supply voltage of the amplifier.
5. The method of claim 1 , monitoring the characteristic of the amplifier includes detecting a change in at least one of a supply voltage or supply current when the amplifier is turned ON.
6. The method of claim 1 ,
the open-loop control signal based on the characteristic monitored during the previous operating interval is obtained by correcting a prior open-loop control signal based on the characteristic monitored relative to a reference frame.
7. The method of claim 6 ,
comparing the characteristic monitored with a reference,
correcting the prior open-loop control signal if the comparison of the characteristic monitored with the reference exceeds a first threshold,
not correcting the prior open-Loop control signal if the comparison of the characteristic monitored with the reference does not exceed the first threshold.
8. The method of claim 7 ,
resetting the prior open-loop control signal to a default value if the comparison of the characteristic monitored with the reference is less than zero.
9. The method of claim 1 , providing the open-loop control signal to the amplifier includes providing to the amplifier a control signal that is not modified by feedback during an operating interval of the amplifier.
10. The method of claim 1 ,
monitoring the characteristic of the amplifier during the operating interval of the amplifier when the amplifier operates on a signal having a particular frequency;
the open-loop control signal is obtained by updating a prior open-loop control signal based on the characteristic monitored;
storing the updated open-loop control signal in a lock-up table in association with the particular frequency,
applying the stored open-loop control signal to the amplifier when the amplifier operates on a signal having the particular frequency at a future time.
11. A method of operating an amplifier, the method comprising:
activating the amplifier by providing an open-loop control signal to the amplifier;
monitoring a characteristic of the amplifier when the amplifier is active;
generating an updated open-loop control signal based on the characteristic monitored.
12. The method of claim 11 , subsequently activating the amplifier by providing the updated open-loop control signal to the amplifier.
13. The method of claim 11 , storing the updated control signal in a look-up table.
14. The method of claim 11 ,
monitoring the characteristic of the amplifier during multiple active intervals of the amplifier;
generating an updated open-loop control signal based on an average of the characteristic monitored during the multiple active intervals of the amplifier.
15. The method of claim 11 ,
monitoring the characteristic of the amplifier operating at different frequencies during corresponding active intervals of the amplifier;
generating updated open-loop control signals based on the characteristic monitored at the different frequencies, each of the updated open-loop control signals corresponding to a particular one of the different frequencies;
storing each of the updated open-loop control signals in a look-up table in association with its corresponding frequency.
16. The method of claim 11 , monitoring the characteristic of the amplifier includes detecting at least one of an output power of the amplifier, a supply current of the amplifier, and a supply voltage of the amplifier.
17. The method of claim 11 ,
generating the updated open-loop control signal based on the characteristic monitored includes correcting a prior open-loop control signal based on the characteristic monitored relative to a reference frame.
18. The method of claim 11 ,
comparing the characteristic monitored with a reference,
generating the updated open-loop control signal includes correcting a prior open-loop control signal based on the comparison of the characteristic monitored with the reference.
19. The method of claim 18 ,
correcting the prior open-loop control signal if the comparison of the characteristic monitored with the reference exceeds a first threshold,
not correcting the prior open-loop control signal if the comparison of the characteristic monitored with the reference does not exceed the first threshold.
20. The method of claim 19 ,
resetting the prior open-loop control signal to a default value if the comparison of the characteristic monitored with the reference is less than zero.
21. A method in an amplifier, the method comprising:
operating the amplifier during active intervals by providing open-loop control signals to the amplifier;
monitoring a change in load impedance at an output of the amplifier;
providing an open-loop control signal to the amplifier based on the change in load impedance monitored during at least one previous active interval of the amplifier.
22. The method of claim 21 ,
monitoring the change in load impedance by detecting a characteristic of one of a supply current or supply voltage provided to the amplifier,
providing the open-loop control signal to the amplifier based on the characteristic of the supply current or supply voltage monitored.
23. The method of claim 21 ,
obtaining the updated open-loop control signal by correcting a prior open-loop control signal based on a change in load impedance monitored during a previous operating interval of the amplifier.
24. The method of claim 23 ,
comparing a characteristic of the amplifier related to the change in load impedance monitored with a reference,
correcting the prior open-loop control signal if the comparison of the characteristic of the amplifier with the reference exceeds a first threshold,
not correcting the prior open-loop control signal if the comparison of the characteristic monitored with the reference does not exceed the first threshold.
25. The method of claim 24 ,
resetting the prior open-loop control signal to a default value if the comparison of the characteristic monitored with the reference is less than zero.
26. The method of claim 21 ,
storing the updated open-loop control signal,
providing the open-loop control signal to the amplifier based on the change in load impedance monitored during at least one previous active interval of the amplifier by providing the stored updated open-loop control signal to the amplifier.