INTERFERENCE REDUCTION BETWEEN RF COMMUNICATIONS BANDS

• US 20130135052A1
• Filed: 05/24/2012
• Published: 05/30/2013
• Est. Priority Date: 04/20/2010
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Arkiszewski, Roman Zbigniew
• Granted Patent: US 9,214,900 B2
• Time in Patent Office: Days
• US Class Current: 330/295
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 1/0261 with control of the polarisation voltage or current, e.g. gliding Class A
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 2200/171 A filter circuit coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/222 A circuit being added at the input of an amplifier to adapt the input impedance of the amplifier
• CPC Class Codes: H03F 2200/27 A biasing circuit node being switched in an amplifier circuit
• CPC Class Codes: H03F 2200/318 A matching circuit being used as coupling element between two amplifying stages
• CPC Class Codes: H03F 2200/336 A I/Q, i.e. phase quadrature, modulator or demodulator being used in an amplifying circuit
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/411 the output amplifying stage of an amplifier comprising two power stages
• CPC Class Codes: H03F 2200/414 A switch being coupled in the output circuit of an amplifier to switch the output on/off
• CPC Class Codes: H03F 2200/417 A switch coupled in the output circuit of an amplifier being controlled by a circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/504 the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier
• CPC Class Codes: H03F 2200/534 Transformer coupled at the input of an amplifier
• CPC Class Codes: H03F 2200/537 A transformer being used as coupling element between two amplifying stages
• CPC Class Codes: H03F 2200/541 Transformer coupled at the output of an amplifier
• CPC Class Codes: H03F 2203/21106 An input signal being distributed in parallel over the inputs of a plurality of power amplifiers
• CPC Class Codes: H03F 2203/21142 Output signals of a plurality of power amplifiers are parallel combined to a common output
• CPC Class Codes: H03F 2203/21157 A filter circuit being added at the output of a power amplifier stage
• CPC Class Codes: H03F 3/19 : with semiconductor devices only
• CPC Class Codes: H03F 3/195 : in integrated circuits
• CPC Class Codes: H03F 3/211 : using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/245 : with semiconductor devices only
• CPC Class Codes: H03F 3/602 : Combinations of several amplifiers
• CPC Class Codes: H03F 3/68 : Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602
• CPC Class Codes: H03F 3/72 : Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal

Abstract

Radio frequency (RF) power amplifier (PA) circuitry and a PA envelope power supply are disclosed. The RF PA circuitry receives and amplifies an RF input signal to provide an RF output signal using an envelope power supply signal, which is provided by the PA envelope power supply. The RF PA circuitry operates in either a normal RF spectral emissions mode or a reduced RF spectral emissions mode. When reduced RF spectral emissions are required, the RF PA circuitry operates in the reduced RF spectral emissions mode. As such, at a given RF output power, during the reduced RF spectral emissions mode, RF spectral emissions of the RF output signal are less than during the normal RF spectral emissions mode. As a result, the reduced RF spectral emissions mode may be used to reduce interference between RF communications bands.

Claims

1. Circuitry comprising:

radio frequency (RF) power amplifier (PA) circuitry adapted to;

receive and amplify an RF input signal to provide an RF output signal using an envelope power supply signal;

operate in one of a normal RF spectral emissions mode and a reduced RF spectral emissions mode; and

when reduced RF spectral emissions are required, operate in the reduced RF spectral emissions mode; and

a PA envelope power supply adapted to provide the envelope power supply signal.

2. The circuitry of claim 1 wherein when the reduced RF spectral emissions are not required, the RF PA circuitry is further adapted to operate in the normal RF spectral emissions mode.

3. The circuitry of claim 1 wherein at a given RF output power, during the reduced RF spectral emissions mode, RF spectral emissions of the RF output signal are less than during the normal RF spectral emissions mode.

4. The circuitry of claim 1 wherein:

the RF PA circuitry comprises an RF PA adapted to receive and amplify the RF input signal to provide the RF output signal using the envelope power supply signal;

the RF output signal falls within one of a plurality of RF communications bands;

the plurality of RF communications bands comprises a first RF communications band, which is about adjacent to a second RF communications band; and

when the one of the plurality of RF communications bands is the first RF communications band, reduced RF spectral emissions are required.

5. The circuitry of claim 1 wherein:

the RF PA circuitry comprises an RF PA adapted to receive and amplify the RF input signal to provide the RF output signal using the envelope power supply signal;

the RF output signal falls within one of a plurality of RF communications bands;

the plurality of RF communications bands comprises a first RF communications band, which is about adjacent to a second RF communications band; and

when the one of the plurality of RF communications bands is the first RF communications band and an RF output power from the RF PA is higher than an RF output power threshold, reduced RF spectral emissions are required.

6. The circuitry of claim 5 wherein the first RF communications band is a cellular communications band and the second RF communications band is a non-cellular communications band.

7. The circuitry of claim 6 wherein the first RF communications band is a 3^rd Generation Partnership Project (3GPP) cellular communications band and the second RF communications band is a Public Safety Band.

8. The circuitry of claim 7 wherein a frequency range of the first RF communications band is between about 777 megahertz and about 787 megahertz, and a frequency range of the second RF communications band is between about 788 megahertz and about 798 megahertz.

9. The circuitry of claim 1 wherein:

the RF PA circuitry comprises an RF PA adapted to receive and amplify the RF input signal to provide the RF output signal using the envelope power supply signal; and

during the reduced RF spectral emissions mode, the RF PA has higher PA linearity than during the normal RF spectral emissions mode.

10. The circuitry of claim 9 wherein during the reduced RF spectral emissions mode, the RF PA has a higher PA bias level than during the normal RF spectral emissions mode.

11. The circuitry of claim 10 wherein at a given RF output power, during the reduced RF spectral emissions mode, a magnitude of the envelope power supply signal is higher than during the normal RF spectral emissions mode.

12. The circuitry of claim 9 wherein at a given RF output power, during the reduced RF spectral emissions mode, a magnitude of the envelope power supply signal is higher than during the normal RF spectral emissions mode.

13. The circuitry of claim 9 wherein:

the RF PA is a quadrature RF PA; and

during the reduced RF spectral emissions mode, a quadrature balance of the quadrature RF PA is better than during the normal RF spectral emissions mode.

14. The circuitry of claim 1 wherein:

the RF PA circuitry comprises a quadrature RF PA adapted to receive and amplify the RF input signal to provide the RF output signal using the envelope power supply signal; and

during the reduced RF spectral emissions mode, a quadrature balance of the quadrature RF PA is better than during the normal RF spectral emissions mode.

15. The circuitry of claim 14 wherein:

the quadrature RF PA comprises a quadrature final stage; and

during the reduced RF spectral emissions mode, a bias level of the quadrature final stage is different than during the normal RF spectral emissions mode to improve a quadrature balance of the quadrature final stage.

16. The circuitry of claim 15 wherein:

the quadrature RF PA comprises a quadrature driver stage; and

during the reduced RF spectral emissions mode, a bias level of the quadrature driver stage is different than during the normal RF spectral emissions mode to improve a quadrature balance of the quadrature driver stage.

17. The circuitry of claim 14 wherein:

the quadrature RF PA comprises a quadrature driver stage; and

during the reduced RF spectral emissions mode, a bias level of the quadrature driver stage is different than during the normal RF spectral emissions mode to improve a quadrature balance of the quadrature driver stage.

18. The circuitry of claim 1 wherein the RF PA circuitry is hardwired to select the reduced RF spectral emissions mode.

19. The circuitry of claim 1 wherein the RF PA circuitry comprises:

an RF PA adapted to receive and amplify the RF input signal to provide the RF output signal using the envelope power supply signal;

PA control circuitry adapted to select the one of the normal RF spectral emissions mode and the reduced RF spectral emissions mode; and

PA bias circuitry coupled between the PA control circuitry and the RF PA.

20. The circuitry of claim 19 wherein:

the RF PA circuitry further comprises a PA-digital communications interface (PA-DCI) coupled between a digital communications bus and the PA control circuitry; and

the PA control circuitry is further adapted to receive information via the digital communications bus and select the one of the normal RF spectral emissions mode and the reduced RF spectral emissions mode based on the information.

21. The circuitry of claim 20 wherein:

the RF output signal falls within one of a plurality of RF communications bands; and

the information identifies the one of the plurality of RF communications bands.

22. The circuitry of claim 21 wherein the information is indicative of an RF output power from the RF PA.

23. The circuitry of claim 21 wherein the information is indicative of a magnitude of the envelope power supply signal.

24. A method comprising:

receiving and amplifying a radio frequency (RF) input signal to provide an RF output signal using an envelope power supply signal;

operating in one of a normal RF spectral emissions mode and a reduced RF spectral emissions mode;

when reduced RF spectral emissions are required, operating in the reduced RF spectral emissions mode; and

providing the envelope power supply signal.