Method and apparatus for control of transmitter power consumption

• US 20070171997A1
• Filed: 08/23/2006
• Published: 07/26/2007
• Est. Priority Date: 08/25/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Weissman, Haim, Carmel, Yuval
• Granted Patent: US 7,711,070 B2
• Time in Patent Office: Days
• US Class Current: 375/297
• 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 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/0211 with control of the supply voltage or current
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 2200/511 Many discrete supply voltages or currents or voltage levels can be chosen by a control signal in an IC-block amplifier circuit
• CPC Class Codes: H03F 2200/516 Some amplifier stages of an amplifier use supply voltages of different value
• CPC Class Codes: H03F 2203/21109 An input signal being distributed by switching to a plurality of paralleled power amplifiers
• CPC Class Codes: H03F 2203/21145 Output signals are combined by switching a plurality of paralleled power amplifiers to a common output
• CPC Class Codes: H03F 2203/7239 the gated amplifier being switched on or off by putting into parallel or not, by choosing between amplifiers and shunting lines by one or more switch(es)
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated
• 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 2001/045 with means for improving efficiency
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A method and apparatus improve the design and control of amplification stages in a radio frequency (RF) transmitter, so as to reduce its power consumption. In some aspects, the transmitter is operable to transmit an output RF signal at a target power level, which may vary over a wide dynamic range. For each target power level in the dynamic range, a control module in the transmitter configures operational settings of amplification stages of the transmitter in order to produce the output RF signal having the appropriate target power level, while consuming minimal power from the power source.

Claims

1. A method for controlling a radio frequency (RF) transmitter that includes one or more amplification stages, the method comprising:

defining a range of transmit power levels over which the transmitter is required to operate;

determining a statistical distribution of the transmit power levels in the range that is expected to occur during use of the transmitter;

responsively to the statistical distribution, dividing the range into a plurality of sub-ranges and determining, for each sub-range, one or more operational settings of at least one of the amplification stages; and

configuring the transmitter to determine a target power level of an output RF signal during the use of the transmitter and to apply the one or more operational settings depending upon the sub-range in which the target power level falls.

2. The method according to claim 1, wherein dividing the range and determining the operational settings comprise choosing the sub-ranges and settings so as to reduce electrical power drawn by the transmitter in view of the statistical distribution.

3. The method according to claim 1, wherein the one or more amplification stages have a set of configurable parameters, and wherein determining the operational settings comprises choosing a subset of the parameters to which the operational settings are to apply, and disabling configurability of at least one of the parameters that is not in the subset.

4. The method according to claim 1, wherein the RF transmitter is part of a low duty-cycle (LDC) terminal in an LDC network.

5. The method according to claim 1, wherein the one or more operational settings comprise at least one of a supply voltage, a bias voltage and a bypass condition, and wherein configuring the transmitter comprises at least one of modifying a supply voltage, modifying a bias voltage and bypassing at least one of the one or more amplification stages.

6. The method according to claim 5, wherein at least one of the operational settings comprises the bypass condition, wherein the transmitter is operated in accordance with a half-duplex protocol alternating between a reception mode and a transmission mode, and wherein configuring the transmitter comprises applying the bypass condition to bypass the at least one of the one or more amplification stages and alternating between the reception mode and the transmission mode using a single RF switch.

7. The method according to claim 5, wherein at least one of the operational settings comprises the bypass condition, wherein the transmitter comprises a multiple-band transmitter coupled to transmit on one of multiple frequency bands, and wherein configuring the transmitter comprises applying the bypass condition to bypass the at least one of the one or more amplification stages and selecting one of the multiple frequency bands using an RF switch.

8. The method according to claim 1, wherein dividing the range comprises reducing at least one of a number of the sub-ranges and the number of the operational settings responsively to the statistical distribution.

9. The method according to claim 1, wherein configuring the transmitter comprises programming the transmitter to select the operational settings using at least one of a state machine and a look-up table (LUT).

10. A radio frequency (RF) transmitter, comprising:

one or more amplification stages, which are arranged to produce an output RF signal, wherein at least one of the amplification stages is configurable using one or more operational settings, and wherein the one or more operational settings are determined by defining a range of transmit power levels over which the transmitter is required to operate, determining a statistical distribution of the transmit power levels in the range that is expected to occur during use of the transmitter, dividing the range responsively to the statistical distribution into a plurality of sub-ranges, and determining, for each sub-range, the one or more operational settings of at least one of the amplification stages; and

a control module, which is arranged to determine a target power level of the output RF signal during the use of the transmitter and to apply the one or more operational settings to the at least one of the amplification stages depending upon the sub-range in which the target power level falls.

11. The transmitter according to claim 10, and comprising a power source, which is arranged to provide electrical power for operating the transmitter, wherein the sub-ranges and settings are chosen so as to reduce electrical power drawn by the transmitter from the power source in view of the statistical distribution.

12. The transmitter according to claim 10, wherein the one or more amplification stages have a set of configurable parameters, and wherein the sub-ranges and settings are chosen so as to select a subset of the parameters to which the operational settings are to apply, and disabling configurability of at least one of the parameters that is not in the subset.

13. The transmitter according to claim 10, wherein the transmitter is further coupled to operate as part of a low duty-cycle (LDC) terminal in an LDC network.

14. The transmitter according to claim 10, wherein the one or more operational settings comprise at least one of a supply voltage, a bias voltage and a bypass condition, and wherein the control module is coupled to apply the one or more operational settings by performing at least one of modifying a supply voltage, modifying a bias voltage and bypassing at least one of the one or more amplification stages.

15. The transmitter according to claim 14, wherein at least one of the operational setting comprises the bypass condition, wherein the transmitter is operated in accordance with a half-duplex protocol alternating between a reception mode and a transmission mode, and comprising an RF switch controlled by the control module, the switch coupled to apply the bypass condition to bypass the at least one of the one or more amplification stages, and to alternate between the reception mode and the transmission mode.

16. The transmitter according to claim 14, wherein at least one of the operational settings comprises the bypass condition, wherein the transmitter comprises a multiple-band transmitter coupled to transmit on one of multiple frequency bands, and comprising an RF switch controlled by the control module, the switch coupled to apply the bypass condition to bypass the at least one of the one or more amplification stages, and to select one of the multiple frequency bands.

17. The transmitter according to claim 10, wherein the sub-ranges are represented using at least one of a state machine and a look-up table (LUT).

18. A half-duplex transmitter, which is configured to alternate between a reception mode and a transmission mode, the transmitter comprising:

a transmission circuit, which is operative to produce an output signal for transmission in the transmission mode, the transmission circuit comprising an amplification stage;

a reception circuit, which is operative to receive an input signal in the reception mode;

a switch, which is coupled to the transmission and reception circuits so as both to switch between the reception mode and the transmission mode and to selectably bypass the amplification stage in the transmission mode; and

a control module, which is arranged to determine a target power level of the output signal and to control actuation of the switch so as to select the transmission or the reception mode and, responsively to the target power level, to bypass the amplification stage in the transmission mode.

19. The transmitter according to claim 18, wherein the switch is a single-pole switch, having at least a first throw position for the reception mode, a second throw position for accepting the output signal in the transmission mode from the amplification stage, and a third throw position for accepting the output signal in the transmission mode while bypassing the amplification stage.

20. The transmitter according to claim 18, wherein the control module is arranged to determine whether to bypass the amplification stage depending on a sub-range in which the target power level falls, the sub-range being selected from a plurality of sub-ranges, wherein the sub-ranges are defined by determining a range of transmit power levels over which the transmitter is required to operate, determining a statistical distribution of the transmit power levels in the range that is expected to occur during use of the transmitter and dividing the range responsively to the statistical distribution into the plurality of sub-ranges.

21. A transmitter, comprising:

a first amplification stage, which is coupled to produce a first output signal in a first frequency band;

a second amplification stage, which is coupled to produce a second output signal in a second frequency band;

an RF switch, which is coupled both to selectably bypass the first and second amplification stages and to select between the first and second frequency bands; and

a control module, which is arranged to determine a target power level of at least one of the first and second output signals and to control actuation of the switch so as to select between the first and second frequency bands and, responsively to the target power level, to bypass at least one of the first and second amplification stages.

22. The transmitter according to claim 21, wherein the switch is a single-pole switch, having at least a first throw position for accepting the first output signal while not bypassing the first amplification stage, a second throw position for accepting the second output signal while not bypassing the second amplification stage, and a third throw position for accepting one of the first and second output signals while bypassing at least one of the first and second amplification stages.

23. The transmitter according to claim 21, wherein the control module is arranged to determine whether to bypass at least one of the first and second amplification stages depending on a sub-range, in which the target power level falls, the sub-range being selected from a plurality of sub-ranges, wherein the sub-ranges are defined by determining a range of transmit power levels over which the transmitter is required to operate, determining a statistical distribution of the transmit power levels in the range that is expected to occur during use of the transmitter and dividing the range responsively to the statistical distribution into the plurality of sub-ranges.