Broadband power amplifier systems and methods

• US 9,973,153 B2
• Filed: 11/28/2016
• Issued: 05/15/2018
• Est. Priority Date: 04/29/2014
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Samelis, Apostolos
• Primary Examiner(s): Vo, Nguyen
• Assistant Examiner(s): Mathew, Max
• Application Number:
  US15/361,777
• Publication Number:
  US 20170170792A1
• Time in Patent Office: 533 Days
• Field of Search: 455 78
• 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 1/486 with IC amplifier blocks
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/108 A coil being added in the drain circuit of a FET amplifier stage, e.g. for noise reducing purposes
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• 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 2200/318 A matching circuit being used as coupling element between two amplifying stages
• CPC Class Codes: H03F 2200/36 the amplifier comprising means for increasing the bandwidth
• 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 2200/391 the output circuit of an amplifying stage comprising an LC-network
• CPC Class Codes: H03F 2200/402 A series resonance being added in shunt in the output circuit, e.g. base, gate, of an amplifier stage
• 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 2200/421 Multiple switches coupled in the output circuit of an amplifier are controlled by a circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/516 Some amplifier stages of an amplifier use supply voltages of different value
• CPC Class Codes: H03F 2203/7221 the gated amplifier being switched on or off by a switch at the output of the amplifier
• CPC Class Codes: H03F 2203/7236 the gated amplifier being switched on or off by putting into parallel or not, by choosing between amplifiers by (a ) switch(es)
• CPC Class Codes: H03F 3/195 : in integrated circuits
• CPC Class Codes: H03F 3/245 : with semiconductor devices only
• 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: H04B 1/006 : using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/44 : Transmit/receive switching

Abstract

Disclosed are systems, devices, and methodologies to reduce harmonics in a radio frequency output signal. A power amplifier system comprises a power amplifier and a tunable output matching network electrically connected between the output of the power amplifier and an output of the tunable output matching network. The tunable output matching network reduces second-order harmonics in an amplified radio frequency signal when the power amplifier operates in a low frequency mode. The tunable output matching network includes traps such as a series inductor and a first capacitor in series with a first switch, a second capacitor in series with a second switch, and a third capacitor in series with a third switch, where the traps are tuned to selected harmonic frequencies when the power amplifier operates in the low frequency band of the operating band of frequencies.

Claims

1. A power amplifier comprising:

an amplifier circuit configured to operate in a continuous band of frequencies that includes a low band and a high band, receive a radio frequency signal having a fundamental frequency in the continuous band of frequencies, and provide an amplified radio frequency signal along a single transmission path to a single output terminal; and

at least one switched harmonic trap circuit and at least one switched capacitor circuit in the single transmission path and configured to receive the amplified radio frequency signal when the amplifier circuit is operating in the low frequency band and not to receive the amplified radio frequency signal when the amplifier circuit is operating in the high frequency band, each of the at least one switched harmonic trap circuit and the at least one switched capacitor circuit being tunable and further configured to reject harmonic signals of frequencies in the low frequency band that are within the high frequency band from the amplified radio frequency signal when the amplifier circuit is operating in the low frequency band.

2. The power amplifier of claim 1 wherein the at least one switched harmonic trap circuit includes an inductor, a capacitor, and a switch in series communication.

3. The power amplifier of claim 2 wherein the amplifier circuit, the inductor, and the capacitor are implemented on a silicon germanium die.

4. The power amplifier of claim 2 wherein the switch is implemented on a silicon on insulator die.

5. The power amplifier of claim 1 wherein the at least one switched capacitor circuit includes a capacitor in series communication with a switch.

6. The power amplifier of claim 1 wherein the low frequency band is between approximately 470 MHz to approximately 610 MHz and the high frequency band is between approximately 610 MHz to approximately 930 MHz.

7. The power amplifier of claim 1 wherein the power amplifier includes a broadband power amplifier.

8. The power amplifier of claim 1 wherein the switched harmonic trap circuit is configured to create a short circuit to ground for specific harmonic frequencies of the amplified radio frequency signal.

9. The power amplifier of claim 8 wherein at least a portion of signal energy from the specific harmonic frequencies is reflected back to the amplifier circuit for partial recycling.

10. A wireless communication device comprising the power amplifier of claim 1.

11. A wireless communication device comprising:

an antenna configured to transmit and receive radio frequency signals; and

a power amplifier system configured to amplify, and reduce harmonic components in, a radio frequency signal for transmission by the antenna, the power amplifier system including an amplifier circuit configured to operate in a continuous band of frequencies, receive the radio frequency signal having a fundamental frequency in the continuous band, and provide an amplified radio frequency signal in a single transmission path, the power amplifier system further including at least one switched harmonic trap circuit and at least one switched capacitor circuit in the single transmission path and configured to receive the amplified radio frequency signal when the amplifier circuit is operating in the low frequency band and not to receive the amplified radio frequency signal when the amplifier circuit is operating in the high frequency band, each of the at least one switched harmonic trap circuit and the at least one switched capacitor circuit being tunable and configured to reject the harmonic components of frequencies in the low frequency band that are within the high frequency band from the amplified radio frequency signal when the amplifier circuit is operating in the low frequency band.

12. The wireless mobile device of claim 11 wherein the at least one switched harmonic trap circuit includes an inductor, a capacitor and a switch in series communication.

13. The wireless mobile device of claim 12 wherein the amplifier circuit, the inductor, and the capacitor are implemented on a silicon germanium die.

14. The wireless mobile device of claim 12 wherein the switch is implemented on a silicon on insulator die.

15. The wireless mobile device of claim 11 wherein the at least one switched capacitor circuit includes a capacitor in series communication with a switch.

16. A method to reduce harmonic components in a radio frequency signal, the method comprising:

operating a power amplifier circuit in a continuous band of frequencies that includes a low frequency band and a high frequency band;

receiving at an input to the power amplifier circuit a radio frequency signal having a fundamental frequency in the continuous band of frequencies;

amplifying the radio frequency signal with the power amplifier circuit to provide an amplified radio frequency signal in a single transmission path;

receiving the amplified radio frequency signal at an input to a harmonic rejection filter;

filtering the amplified radio frequency signal with the harmonic rejection filter to reduce harmonic components of frequencies in the low frequency band that are within the high frequency band when the power amplifier circuit is operating in the low frequency band, the harmonic rejection filter including at least one switched harmonic trap circuit and at least one switched capacitor circuit; and

switching off the at least one switched harmonic trap and the at least one switched capacitor circuit when the power amplifier circuit is operating in the high frequency band.

17. The method of claim 16 wherein the filtering of the amplified radio frequency signal includes closing a switch in series communication with an inductor and a capacitor, the switch, the inductor, and the capacitor forming the at least one switched harmonic trap circuit.

18. The method of claim 16 wherein the filtering of the amplified radio frequency signal includes closing a switch in series communication with a capacitor, the switch and the capacitor forming the at least one switched capacitor circuit.

19. The method of claim 16 further comprising enhancing the bandwidth of the harmonic rejection filter with a third-order inductance-matching circuit.

20. The method of claim 19 wherein the third-order inductance-matching circuit includes one of the at least one switched capacitor circuits.