Control of 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 signal input for receiving a detection signal representative of a pre-amplified transmission signal sensed at the output of the pre-amplifier by a detector;
a switching regulator control block configured to generate a switching supply control signal by applying a switching control transfer function to the received detection signal, the switching supply control signal comprising control values for a switched mode power supply configured to generate a supply voltage signal for the power amplifier in response to the switching supply control signal, and the switching control transfer function having values determined based on a characterization of the response of the detector, control curves of the switched mode power supply, and a response of the power amplifier to input drive; and
a signal output for providing the switching supply control signal to the switched mode power supply;
wherein, in operation, the switching regulator control block communicates with the detector using the signal input and with the switched mode power supply using the signal output.
2. The control system of claim 1 , wherein the switching regulator control block is configured to generate the switching supply control signal further based on a trim signal generated to compensate for component tolerances.
3. The control system of claim 1 , further comprising a power limit control block configured to generate a gain control signal based on an automatic gain control signal, the received detection signal, and a transmit power limit signal for limiting transmission power of the transmitter, the gain control signal provided to the pre-amplifier for controlling gain in the pre-amplifier.
4. The control system of claim 3 , wherein the power limit control block is implemented in a processor and is configured to apply a power limiting transfer function defined in the processor using one or more look-up tables to generate the gain control signal.
5. The control system of claim 1 , wherein the switching regulator control block is implemented in a processor.
6. The control system of claim 5 , wherein the switching control transfer function is defined in the processor using one or more look-up tables.
7. The control system of claim 1 , wherein the control values for the switched mode power supply are generated to hold the power amplifier in a state of constant compression.
8. The control system of claim 1 , further comprising a compensating control block configured to generate a gain correction signal based on the supply voltage signal, and to adjust an automatic gain control (AGC) signal based on the gain correction signal to generate a gain control signal for controlling gain in the pre-amplifier.
9. 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:
receiving a detection signal representative of a pre-amplified transmission signal sensed at the output of the pre-amplifier by a detector;
generating a switching supply control signal by applying a switching control transfer function to the received detection signal, the switching supply control signal comprising control values for a switched mode power supply configured to generate a supply voltage signal for the power amplifier in response to the switching supply control signal, and the switching control transfer function having values determined based on a characterization of the response of the detector, control curves of the switched mode power supply, and a response of the power amplifier to input drive; and
providing the switching supply control signal to the switched mode power supply.
10. The method of claim 9 , further comprising generating the switching supply control signal based on a trim signal generated to compensate for component tolerances.
11. The method of claim 9 , further comprising generating a gain control signal based on an automatic gain control signal, the received detection signal, and a transmit power limit signal for limiting transmission power of the transmitter, the gain control signal provided to the pre-amplifier for controlling gain in the pre-amplifier.
12. The method of claim 11 , wherein the gain control signal is generated in a processor, and the method further comprises applying a power limiting transfer function defined in the processor using one or more look-up tables to generate the gain control signal.
13. The method of claim 9 , wherein the switching supply control signal is generated in a processor.
14. The method of claim 13 , further comprising defining the switching control transfer function in the processor using one or more look-up tables.
15. The method of claim 9 , further comprising generating the control values for the switched mode power supply to hold the power amplifier in a state of constant compression.
16. The method of claim 9 , further comprising generating a gain correction signal based on the supply voltage signal, and adjusting an automatic gain control (AGC) signal based on the gain correction signal to generate a gain control signal for controlling gain in the pre-amplifier.
17. 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:
receiving a detection signal representative of a pre-amplified transmission signal sensed at the output of the pre-amplifier by a detector;
generating a switching supply control signal by applying a switching control transfer function to the received detection signal, the switching supply control signal comprising control values for a switched mode power supply configured to generate a supply voltage signal for the power amplifier in response to the switching supply control signal, and the switching control transfer function having values determined based on a characterization of the response of the detector, control curves of the switched mode power supply, and a response of the power amplifier to input drive; and
providing the switching supply control signal to the switched mode power supply.
18. The non-transitory computer-readable storage medium of claim 17 , wherein said acts further comprise generating the switching supply control signal based on a trim signal generated to compensate for component tolerances.
19. The non-transitory computer-readable storage medium of claim 17 , wherein said acts further comprise generating a gain control signal based on an automatic gain control signal, the received detection signal, and a transmit power limit signal for limiting transmission power of the transmitter, the gain control signal provided to the pre-amplifier for controlling gain in the pre-amplifier.
20. The non-transitory computer-readable storage medium of claim 19 , wherein said acts further comprise defining the switching control transfer function in the processor using one or more look-up tables.
21. The non-transitory computer-readable storage medium of claim 19 , wherein said acts further comprise applying a power limiting transfer function defined in the processor using one or more look-up tables to generate the gain control signal.
22. The non-transitory computer-readable storage medium of claim 17 , wherein said acts further comprise generating the control values for the switched mode power supply to hold the power amplifier in a state of constant compression.
23. The non-transitory computer-readable storage medium of claim 17 , wherein said acts further comprise generating a gain correction signal based on the supply voltage signal, and adjusting an automatic gain control (AGC) signal based on the gain correction signal to generate a gain control signal for controlling gain in the pre-amplifier.