GB2316561A - Improving the efficiency of a power amplifier by selecting stored values of supply and/or bias voltage in dependence on measured output power - Google Patents
Improving the efficiency of a power amplifier by selecting stored values of supply and/or bias voltage in dependence on measured output power Download PDFInfo
- Publication number
- GB2316561A GB2316561A GB9617641A GB9617641A GB2316561A GB 2316561 A GB2316561 A GB 2316561A GB 9617641 A GB9617641 A GB 9617641A GB 9617641 A GB9617641 A GB 9617641A GB 2316561 A GB2316561 A GB 2316561A
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- United Kingdom
- Prior art keywords
- amplifier
- output power
- efficiency
- output
- power level
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
- H03F1/0205—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers
- H03F1/0211—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers with control of the supply voltage or current
- H03F1/0216—Continuous control
- H03F1/0233—Continuous control by using a signal derived from the output signal, e.g. bootstrapping the voltage supply
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
- Transmitters (AREA)
Abstract
A method of improving the efficiency of a power amplifier in which the voltage applied to an output stage (2) of the power amplifier is varied in accordance with predetermined data as the output power level from the amplifier varies so as to maintain the efficiency of the amplifier at its maximum value. A system for putting the method into practice also is described.
Description
Improved Power Amplifier and Related Method
Field of Invention
The present invention relates to power amplifiers and more specifically, to power amplifiers which are intended for use with mobile radio communication equipment.
Background of Invention
Normally, power amplifiers are so designed that they operate most efficiently at a specific, usually maximum, power and if they are operated at any other output power level, the efficiency of the amplifier is reduced, so increasing the power consumption of the amplifier. Although undesirable, in many cases this characteristic may be acceptable. However, when the input power available is limited, or the power levels involved are high, then the matter is of more importance.
A situation in which the reduction in the efficiency of a power amplifier when it is used at an output power level less than its maximum is of particular importance is cellular radio communication systems of the type in which variations in the power of signals transmitted by base stations or mobile stations are used as a means of limiting interference with other users or operators. In the case of base stations, overall r running g costs are reduced and in the case of mobile stations, the lifetimes of the batteries, which are used to supply power to the devices are increased.
Summat of the Invention
According to the invention in one aspect there is provided a method of improving the efficiency of a power amplifier, comprising the operations of initially measuring the efficiency of the power amplifier as a function of the output power from the amplifier and the supply or/and bias voltage applied to an output stage of the amplifier, determining the value of the output stage supply or/and bias voltage required to maximise the efficiency of the amplifier for a given output power level, storing data relatea thereto, and in use monitoring the output power level from the amplifier and varying the output stage supply or/and bias voltage in accordance with the stored data so as to optimise the efficiency of the amplifier.
Preferably, the power amplifier is a radio.frequency amplifier for use in connection with a cellular radio communication system.
According to the invention in a second aspect there is provided an apparatus for improving the efficiency of a power amplifier, comprising a source of a variable supply or/and bias voltage for an output stage of the amplifier, means for storing data indicative of the output stage supply or/and bias voltage required to maximise the efficiency of the amplifier at a given output power level from the amplifier, means for monitoring the output power level from the amplifier and means for controlling the action of the source of the output stage voltage in accordance with the output power level and the stored data so as to maximise the efficiency of the amplifier
The means for monitoring the output power level from the amplifier may comprise means for varying the output power in a predetermined manner from a nominal value, or means for measuring the output power level directly.
A suitable means for varying the output power level in a predetermined manner may comprise a variable attenuator situated between a gain stage and the output stage of the amplifier.
Preferably the power amplifier is a radio frequency power amplifier for use in a cellular radio communication system.
Brief Description of the Drawings
The invention will now be described, by way of example, with reference to the accompanying drawing which is a block circuit diagram of an embodiment of the invention.
Description of 2 Preferred Embodiment
Referring to the drawing, a power amplifier embodying the invention includes of a variable gain input stage 1 and an output stage 2. The output stage 2 incorporates, three amplifiers 3 in series. The amplifiers 3 are supplied with a single voltage by a variable voltage source 4, to which a fixed voltage from a source 5 is applied The input stage 1 includes an amplifier 6.
Situated between the input stage 1 and the output stage 2 of the power amplifier is a variable attenuator 7. The actions of the variable voltage source 4 and the variable attenuator 7 are controlled by a control unit 8 to which data relating to the optimum output stage supply or/and bias voltage required for a given output power level from the amplifier are applied from a data store 9.
Initially, the required data are established by applying a fixed signal to the input stage 1 of the amplifier, measuring the output power from the output stage 2 of the amplifier and varying the applied output supply or/and bias voltage until the d.c. current drawn from the variable voltage source 4 is a minimum. This voltage is measured and stored, together with the output power level, in store 9. The setting of the variable attenuator 7 is then varied to provide a lower output power level from the output stage 2 of the amplifier. This lower output power level can either be measured directly, or inferred from the setting of the variable attenuator 7. Again, the applied output stage supply or/and bias voltage is varied until the d.c. current drawn from the variable voltage source 4 is a minimum, and this voltage, together with the value of the output power level, either in absolute or relative terms, is stored in the store 9. This procedure is repeated as often as is desired.
The system is then ready for use.
A particular use of the invention is in time divided multiple access cellular radio communication systems in which the power of signals, transmitted by base stations, and in some cases mobile stations, is used as a means for enabling a base station to discriminate between one mobile station or another. One such system is that known by the acronym GSM (Global
System for Mobile Communications) in which 15 power settings-differing by 2 dB and time slots of about 500 Rs are used.
The variable voltage source 4, variable attenuator 7 and control system 8 all have to be capable of operating within this limit.
Another use for the invention is in cellular radio communication systems, again one of which is the system known as GSM, in which the power level of signals transmitted from base stations is used as a means of regulating traffic flow in cells of the cellular radio communication system.
Claims (15)
1. A method of improving the efficiency of a power amplifier, comprising the operations of initially measuring the efficiency of the power amplifier as a function of the output power from the amplifier and the supply or/and bias voltage applied to an output stage of the amplifier, determining the value of the output stage supply or/and bias voltage required to maximise the efficiency of the amplifier for a given output power level, storing data related thereto, and in use monitoring the output power level from the amplifier and varying the output stage voltage in accordance with the stored data so as to optimise the efficiency of the amplifier.
2 A method according to claim 1 wherein the output power level from the amplifier is determined absolutely.
3. A method according to claim 1 wherein the output power from the amplifier is determined relative to a maximum output power level.
4. A method according to any of claims 1 to 3 wherein the.power amplifier forms part of a time divided multiple access cellular radio communication system and the monitoring of the output signal level from the amplifier and subsequent varying of the output stage supply or/and bias voltage are carried out discontinuously within separate time division periods of the time division multiple access cellular radio communication system.
5. An apparatus for improving the efficiency of a power amplifier, comprising a source of a variable supply or/and bias voltage for an output stage of the amplifier, means for storing data indicative of the output stage supply or/and bias voltage required to maximize the efficiency of the amplifier at a given output power level from the amplifier, means for monitoring the output power level from the amplifier and means for controlling the action of the source of the output stage voltage in accordance with the output power level and the stored data so as to maximise the efficiency of the amplifier.
6. An apparatus according to claim 5 wherein there is included means for measuring the output power from the amplifier absolutely
7. Apparatus according to claim 5 wherein the means for monitoring the output power level from the amplifier comprises means for varying the output power in a predetermined manner from a nominal value.
8. An apparatus according to claim 6 or claim 7 wherein there is included a variable attenuator situated between an input stage and the output stage of the amplifier and there is included a controller adapted to vary the degree of attenuation provided by the antenna thereby to vary the output power from the amplifier accordingly.
9. An apparatus according to claim 5 wherein the controller is adapted to vary the degree of attenuation provided by the variable attenuator in discrete steps.
10. An apparatus according to any of claims 5 to 9 wherein the amplifier is adapted to form part of a pulsed radio communication systems.
11. An apparatus according to claim 10 wherein the controller is adapted to vary the degree of attenuation provided by the variable attenuator and the output voltage within a single pulse of the pulsed radio communication system.
12. An apparatus according to claim 10 or claim 11 wherein the pulsed radio communication system is a time divided multiple access system.
13. An apparatus according to any of claims 10 to 12 wherein the pulsed radio communication system is adapted to conform to the specifications of the system known as global system for mobile communications.
14. A method of improving the efficiency of a power amplifier substantially as herein before described and with reference to the accompanying drawing.
15. An apparatus for improving the efficiency of a power amplifier substantially as herein before described and with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9617641A GB2316561B (en) | 1996-08-22 | 1996-08-22 | Improved power amplifier and related method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9617641A GB2316561B (en) | 1996-08-22 | 1996-08-22 | Improved power amplifier and related method |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9617641D0 GB9617641D0 (en) | 1996-10-02 |
| GB2316561A true GB2316561A (en) | 1998-02-25 |
| GB2316561B GB2316561B (en) | 2001-01-03 |
Family
ID=10798833
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9617641A Expired - Fee Related GB2316561B (en) | 1996-08-22 | 1996-08-22 | Improved power amplifier and related method |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2316561B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2329087A (en) * | 1997-09-08 | 1999-03-10 | Motorola Inc | Improving the efficiency of a transmitter amplifier by controlling an amplifier voltage using a voltage conditioner such as a switched mode converter |
| GB2332997A (en) * | 1997-12-31 | 1999-07-07 | Samsung Electronics Co Ltd | Dynamic control to improve the efficiency of a variable power amplifier |
| WO2002043240A1 (en) * | 2000-11-24 | 2002-05-30 | Qualcomm Incorporated | Amplifier circuit |
| GB2393595A (en) * | 2002-09-26 | 2004-03-31 | Qualcomm | Calibration and control of gain and current of transmitter amplifier to improve linearity and efficiency |
| GB2395077A (en) * | 2002-11-01 | 2004-05-12 | N & L Ltd | An amplifier arrangement linearised by predistortion and feedforward; adaptive bias for improved efficiency; thermal overload protection |
| RU203913U1 (en) * | 2021-02-09 | 2021-04-28 | Акционерное общество "Ижевский мотозавод "Аксион-холдинг" | Broadband power amplifier for radio transmitting device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2294833A (en) * | 1994-11-01 | 1996-05-08 | Motorola Inc | Increasing amplifier efficiency using variable bias |
-
1996
- 1996-08-22 GB GB9617641A patent/GB2316561B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2294833A (en) * | 1994-11-01 | 1996-05-08 | Motorola Inc | Increasing amplifier efficiency using variable bias |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2329087A (en) * | 1997-09-08 | 1999-03-10 | Motorola Inc | Improving the efficiency of a transmitter amplifier by controlling an amplifier voltage using a voltage conditioner such as a switched mode converter |
| GB2332997A (en) * | 1997-12-31 | 1999-07-07 | Samsung Electronics Co Ltd | Dynamic control to improve the efficiency of a variable power amplifier |
| GB2332997B (en) * | 1997-12-31 | 1999-11-24 | Samsung Electronics Co Ltd | Dynamic control of a variable power amplifier |
| WO2002043240A1 (en) * | 2000-11-24 | 2002-05-30 | Qualcomm Incorporated | Amplifier circuit |
| US7196584B2 (en) | 2000-11-24 | 2007-03-27 | Qualcomm Incorporated | Amplifier circuit |
| CN100347951C (en) * | 2000-11-24 | 2007-11-07 | 高通股份有限公司 | Amplifier circuit |
| GB2393595A (en) * | 2002-09-26 | 2004-03-31 | Qualcomm | Calibration and control of gain and current of transmitter amplifier to improve linearity and efficiency |
| GB2427772A (en) * | 2002-09-26 | 2007-01-03 | Qualcomm Inc | Control of gain and bias current of a transmitter to improve linearity and efficiency |
| GB2393595B (en) * | 2002-09-26 | 2007-04-04 | Qualcomm | A transmitter and a method of calibrating power in signals output from a transmitter |
| GB2427772B (en) * | 2002-09-26 | 2007-04-11 | Qualcomm Inc | A transmitter |
| GB2395077A (en) * | 2002-11-01 | 2004-05-12 | N & L Ltd | An amplifier arrangement linearised by predistortion and feedforward; adaptive bias for improved efficiency; thermal overload protection |
| RU203913U1 (en) * | 2021-02-09 | 2021-04-28 | Акционерное общество "Ижевский мотозавод "Аксион-холдинг" | Broadband power amplifier for radio transmitting device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9617641D0 (en) | 1996-10-02 |
| GB2316561B (en) | 2001-01-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20010822 |