Method of power amplifier switching power control using post power amplifier power detection

• US 8,620,238 B2
• Filed: 07/23/2010
• Issued: 12/31/2013
• Est. Priority Date: 07/23/2010
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Chan, Wen-Yen, Khan, Nasserullah, Chung, Ian Ka Yin, Bari, Hamza Mohaimeen
• Primary Examiner(s): Jackson, Blane J
• Application Number:
  US12/842,126
• Publication Number:
  US 20120021704A1
• Time in Patent Office: 1,257 Days
• Field of Search: 455/115.1, 455/126, 455/127.1, 455/127.2, 455/127.3, 455/127.5
• US Class Current: 455/127.1
• CPC Class Codes: H03F 1/02 Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03G 11/00 Limiting amplitude; Limiting rate of change of amplitude ; Clipping in general
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 2001/0416 having gain or transmission power control
• CPC Class Codes: H04B 2001/045 with means for improving efficiency

Abstract

Various embodiments described herein relate to a power management block and one or more amplification blocks 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, both of which are included in a selected one of the amplification blocks. 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. Post power amplifier transmission power is detected for input into the one or more feedback loops executed in the power management block. A controller for the power amplifier is design to stabilize the system with respect to gain expansion in the power amplifier.

Claims

1. A transmitter for a mobile device comprising:

a power amplifier for generating an amplified transmission signal;

a detector coupled to receive an output of the power amplifier and configured to provide a detected amplified transmission signal; and

a power management block comprising;

a switching regulator control block included in a switching regulator control loop, the switching regulator control block configured to generate a power supply control signal by applying a switching control transfer function to the detected amplified transmission signal, the switching control transfer function comprising poles located to stabilize the switching regulator control loop for gain expansion in the power amplifier; and

a switched mode power supply located in the switching regulator control loop and coupled to the switching regulator control block, the switched more power supply being configured to generate a supply voltage signal for the power amplifier based on the power supply control signal.

2. The transmitter of claim 1, wherein the poles of the switching control transfer function are located based on a characterization of the detector, control curves of the switched mode power supply, and a response of the power amplifier to input drive and supply voltage.

3. The transmitter of claim 1, wherein the poles of the switching control transfer function are further located to stabilize the switching regulator control loop for environmental or operating conditions of the power amplifier.

4. The transmitter of claim 1, wherein the switching regulator control block is configured to generate the power supply control signal comprising control values for the switched mode power supply that cause clipping of the amplified transmission signal.

5. The transmitter of claim 1, wherein the transmitter further comprises:

a plurality of power amplifiers; and

at least one switch configured to couple outputs of each or a selected one of the power amplifiers to the detector to provide the detected amplified transmission signal,

wherein each of the power amplifiers are optimized for a different transmission band used by the transmitter.

6. The transmitter of claim 1, wherein the power management block comprises a compensating control block coupled to the switched mode power supply and configured to generate a gain correction signal based on the supply voltage signal, the gain correction signal for modifying an automatic gain control signal to generate a gain control signal provided to a pre-amplifier for controlling pre-amplifier gain.

7. The transmitter of claim 6, wherein the power management block comprises a power limit control block coupled to the detector for limiting a transmission power of the amplified transmission signal, the power limit control block configured to generate the gain control signal based on a transmit power limit signal, the detected amplified transmission signal and the automatic gain control signal.

8. A mobile device comprising:

a processor configured to control the operation of the mobile device;

a transmitter connected to the processor and configured to send and receive data, the transmitter comprising;

a power amplifier for generating an amplified transmission signal;

a detector coupled to receive an output of the power amplifier and configured to provide a detected amplified transmission signal; and

a power management block comprising a switching regulator control block included in a switching regulator control loop, the switching regulator control block configured to generate a power supply control signal by applying a switching control transfer function to the detected amplified transmission signal, the switching control transfer function comprising poles located to stabilize the switching regulator control loop for gain expansion in the power amplifier; and

a switched mode power supply located in the switching regulator control loop and coupled to the switching regulator control block, the switched more power supply being configured to generate a supply voltage signal for the power amplifier based on the power supply control signal.

9. The mobile device of claim 8, wherein the poles of the switching control transfer function are located based on a characterization of the detector, control curves of the switched mode power supply, and a response of the power amplifier to input drive and supply voltage.

10. The mobile device of claim 8, wherein the poles of the switching control transfer function are further located to stabilize the switching regulator control loop for environmental or operating conditions of the power amplifier.

11. The mobile device of claim 8, wherein the switching regulator control block is configured to generate the power supply control signal comprising control values for the switched mode power supply that cause clipping of the amplified transmission signal.

12. The mobile device of claim 8, wherein the transmitter comprises:

a plurality of power amplifiers; and

at least one switch configured to couple each or a selected one of the power amplifiers to the detector to provide the detected amplified transmission signal, wherein each of the power amplifiers are optimized for a different transmission band used by the transmitter.

13. The mobile device of claim 8, wherein the power management block comprises a compensating control block coupled to the switched mode power supply and configured to generate a gain correction signal based on the supply voltage signal, the gain correction signal for modifying an automatic gain control signal to generate a gain control signal provided to a pre-amplifier for controlling pre-amplifier gain.

14. The mobile device of claim 13, wherein the power management block comprises a power limit control block coupled to the detector for limiting a transmission power of the amplified transmission signal, the power limit control block configured to generate the gain control signal based on a transmit power limit signal, the detected amplified transmission signal and the automatic gain control signal.

15. A method of providing a supply voltage signal to a power amplifier, the method comprising:

generating an amplified transmission signal using the power amplifier;

detecting an output of the power amplifier using a detector to provide a detected amplified transmission signal;

generating a power supply control signal by applying a switching control transfer function to the detected amplified transmission signal, the switching control transfer function comprising poles located to stabilize a switching regulator control loop for gain expansion in the power amplifier; and

generating the supply voltage signal by providing the power supply control signal to a switched mode power supply.

16. The method of claim 15, further comprising locating the poles of the switching control transfer function based on a characterization of the detector, control curves of the switched mode power supply, and a response of the power amplifier to input drive and supply voltage.

17. The method of claim 15, wherein the method comprises deriving the switching control transfer function to have poles located to stabilize the switching regulator control loop for environmental or operating conditions of the power amplifier.

18. The method of claim 15, wherein the method comprises generating the power supply control signal to have control values for the switched mode power supply that cause clipping of the amplified transmission signal.

19. The method of claim 15, wherein there are additional power amplifiers and the method further comprises coupling outputs of each of the power amplifiers to the detector to provide the detected amplified transmission signal, wherein each of the power amplifiers are optimized for a different transmission band.

20. The method of claim 15, wherein the method further comprises generating a gain correction signal based on the supply voltage signal, and modifying an automatic gain control signal based on the gain correction signal to generate a gain control signal provided to the pre-amplifier for controlling pre-amplifier gain.

21. The method of claim 20, wherein the method further comprises limiting a transmission power of the amplified transmission signal by generating the gain control signal based on a transmit power limit signal, the detected amplified transmission signal and the automatic gain control signal.