Input drive control for switcher regulated power amplifier modules
Various embodiments described herein relate to a power management block and an amplification block used in the transmitter of a communication subsystem. The power management block provides improved control for the gain control signal provided to a pre-amplifier and the supply voltage provided to a power amplifier which are both in the amplification block. The power expended by the power amplifier is optimized by employing a continuous control method in which one or more feedback loops are employed to take into account various characteristics of the transmitter components and control values.
1. A control system for a transmitter of a wireless device, the transmitter having a pre-amplifier and a power amplifier coupled to an output of the pre-amplifier, the control system comprising:
a switching regulator control block configured to generate a switching supply control signal based on a pre-amplified transmission signal detected at the output of the pre-amplifier, the switching supply control signal comprising control values for controlling a switched mode power supply to generate a supply voltage signal for the power amplifier based on the pre-amplified transmission signal, in response to the control values of the switching supply control signal; and
a compensating control block configured to generate a gain correction signal based on the supply voltage signal generated by the switched mode power supply, the gain correction signal for adjusting a gain control signal provided to the pre-amplifier for controlling gain in the pre-amplifier.
2. The control system of claim 1 , further comprising a summer configured to generate the gain control signal by subtracting the gain correction signal from an automatic gain control signal.
3. The control system of claim 1 , further comprising:
a summer configured to subtract the gain correction signal from an automatic gain control signal to generate a modified automatic gain control signal; and
a power limit control block configured to generate the gain control signal based on the modified automatic gain control signal, the pre-amplified transmission signal, and a transmit power limit signal for limiting transmission power of the transmitter.
4. The control system of claim 1 , wherein at least one of the switching regulator control block and the compensating control block are implemented in a processor.
5. The control system of claim 4 , wherein at least one of the switching regulator control block and the compensating control block are configured to apply a transfer function.
6. The control system of claim 5 , wherein the transfer function is defined in the processor using one or more look-up tables.
7. The control system of claim 3 , wherein the power limit control block is implemented in a processor and is configured to apply a transfer function defined in the processor using one or more look-up tables to generate the gain control signal.
8. A method of controlling a transmitter of a wireless device, the transmitter having a pre-amplifier and a power amplifier coupled to an output of the pre-amplifier, the method comprising:
generating a switching supply control signal based on a pre-amplified transmission signal detected at the output of the pre-amplifier, the switching supply control signal comprising control values for controlling a switched mode power supply;
providing the switching supply control signal to the switched mode power supply to generate a supply voltage signal for the power amplifier based on the pre-amplified transmission signal, in response to the control values of the switching supply control signal;
generating a gain correction signal based on the supply voltage signal;
adjusting a gain control signal using the gain correction signal, the gain control signal for controlling gain in the pre-amplifier; and
providing the gain control signal to the pre-amplifier.
9. The method of claim 8 , further comprising subtracting the gain correction signal from an automatic gain control signal to generate the gain control signal.
10. The method of claim 8 , further comprising
subtracting the gain correction signal from an automatic gain control signal to generate a modified automatic gain control signal; and
generating the gain control signal based on the modified automatic gain control signal, the pre-amplified transmission signal, and a transmit power limit signal for limiting transmission power of the transmitter.
11. The method of claim 8 , wherein at least one of the switching supply control signal and the gain correction signal are generated in a processor.
12. The method of claim 11 , further comprising applying a transfer function to generate at least one of the switching supply control signal and the gain correction signal.
13. The method of claim 12 , further comprising defining the transfer function in the processor using one or more look-up tables.
14. The method of claim 10 , wherein the gain control signal is generated in a processor, and the method further comprises applying a transfer function defined in the processor using one or more look-up tables to generate the gain control signal.
15. A non-transitory computer-readable storage medium storing instructions executable by a processor coupled to the storage medium, the instructions, when executed by the processor, cause the processor to perform acts of a method of controlling a transmitter of a wireless device, the transmitter having a pre-amplifier and a power amplifier coupled to an output of the pre-amplifier, said acts comprising:
generating a switching supply control signal based on a pre-amplified transmission signal detected at the output of the pre-amplifier, the switching supply control signal comprising control values for controlling a switched mode power supply;
providing the switching supply control signal to the switched mode power supply to generate a supply voltage signal for the power amplifier based on the pre-amplified transmission signal, in response to the control values of the switching supply control signal;
generating a gain correction signal based on the supply voltage signal;
adjusting a gain control signal using the gain correction signal, the gain control signal for controlling gain in the pre-amplifier; and
providing the gain control signal to the pre-amplifier.
16. The non-transitory computer-readable storage medium of claim 15 , wherein said acts further comprise subtracting the gain correction signal from an automatic gain control signal to generate the gain control signal.
17. The non-transitory computer-readable storage medium of claim 15 , wherein said acts further comprise:
subtracting the gain correction signal from an automatic gain control signal to generate a modified automatic gain control signal; and
generating the gain control signal based on the modified automatic gain control signal, the pre-amplified transmission signal, and a transmit power limit signal for limiting transmission power of the transmitter.
18. The non-transitory computer-readable storage medium of claim 15 , wherein said acts further comprise applying a transfer function to generate at least one of the switching supply control signal and the gain correction signal.
19. The non-transitory computer-readable storage medium of claim 18 , wherein said acts further comprise defining the transfer function in the processor using one or more look-up tables.
20. The non-transitory computer-readable storage medium of claim 17 , wherein said acts further comprise applying a transfer function defined in the processor using one or more look-up tables to generate the gain control signal.