RF Power Amplifiers with Linearization

• US 20110068873A1
• Filed: 09/30/2010
• Published: 03/24/2011
• Est. Priority Date: 05/27/2008
• Status: Active Grant

• Current Assignee: Gula Consulting Limited Liability Company (Intellectual Ventures LLC)
• Original Assignee: Rayspan Corporation
• Inventors: Lee, Woo Yong, Dupuy, Alexandre, Alidio, Raul, Achour, Maha, Gummalla, Ajay
• Granted Patent: US 8,368,470 B2
• Time in Patent Office: Days
• US Class Current: 330/295
• CPC Class Codes: H03F 1/0266 by using a signal derived from the input signal
• CPC Class Codes: H03F 1/0272 by using a signal derived from the output signal
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 1/3223 using feed-forward H03F1/3211 takes precedence
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• CPC Class Codes: H03F 2200/105 A non-specified detector of the power of a signal being used in an amplifying circuit
• 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 2200/18 the bias of the gate of a FET being controlled by a control signal
• 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 2200/255 Amplifier input adaptation especially for transmission line coupling purposes, e.g. impedance adaptation
• 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 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/423 Amplifier output adaptation especially for transmission line coupling purposes, e.g. impedance adaptation
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/99 A diode as rectifier being used as a detecting circuit in an amplifying circuit
• 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 2203/21139 An impedance adaptation circuit being added at the output of a power amplifier stage
• 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 2203/21163 : An output signal dependant signal being measured by power measuring, e.g. by an inductive coupler, at the output of a power amplifier
• CPC Class Codes: H03F 2203/21166 : An output signal dependant signal being measured by voltage measuring at the output of a power amplifier
• CPC Class Codes: H03F 2203/21178 : Power transistors are made by coupling a plurality of single transistors in parallel
• CPC Class Codes: H03F 2203/7206 : the gated amplifier being switched on or off by a switch in the bias circuit of the amplifier controlling a bias voltage in 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 3/211 : using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/245 : with semiconductor devices only
• CPC Class Codes: H03F 3/604 : using FET's
• CPC Class Codes: H03F 3/605 : Distributed 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
• CPC Class Codes: H03G 1/0088 : using discontinuously variable devices, e.g. switch-operated

Abstract

Designs and techniques associated with power amplifiers for amplifying RF signals to provide variable power amplification and improved linearity in various RF amplification circuits, including power amplifiers operated under the power back-off conditions.

Claims

1-37. -37. (canceled)

38. A variable power amplifier, comprising:

a plurality of cells, each cell having at least one bank of transistors; and

a control circuit for turning on and off the plurality of cells so as to adjust an output power level of the variable power amplifier to maintain linear operation of the variable power amplifier.

39. The variable power amplifier as in claim 38, wherein the control circuit increases an output current of the variable power amplifier in response to an input voltage level so as to expand a linear operating region of the variable power amplifier at a peak power level.

40. The variable power amplifier as in claim 39, wherein the control circuit increases an operating efficiency of the variable power amplifier at a power back-off condition.

41. The variable power amplifier as in claim 38, wherein the plurality of cells comprise a configuration of switchable transistor banks, and wherein each switchable transistor bank has an individual bias control.

42. The variable power amplifier as in claim 41, wherein the output power level is varied by selectively switching on and off one or more of the switchable transistor banks and selectively biasing the switchable transistor banks.

56. The variable power amplifier as in claim 38, wherein a first cell and a second cell of the plurality of cells have different transistor configurations.

57. The variable power amplifier as in claim 38, wherein the variable power amplifier has a distributed power amplifier architecture comprising a plurality of transmission line structures.

58. The variable power amplifier as in claim 57, wherein the plurality of transmission line structures are Composite Right/Left Handed (CRLH)-based structures each having a shunt inductance, a shunt capacitance, a series inductance and a series capacitance.

59. The variable power amplifier as in claim 58, further comprising an input load to absorb input reflections and an output matching network to adjust the output power level.

60. The variable power amplifier as in claim 59, wherein the input load is a CRLH input matching network, and the output matching network is a CRLH output matching network.

61. The variable power amplifier as in claim 59, wherein the control circuit controls at least one cell to vary the output power level.

62. The variable power amplifier as in claim 61, wherein the control circuit supplies control voltages to individual banks of the at least one bank of transistors so as to selectively switch on and off the individual banks.

63. The variable power amplifier as in claim 38, wherein the control circuit is a feedback mechanism, and acts to increase a power saturation level on detection of peak signals.

64. The variable power amplifier as in claim 60, wherein the control circuit detects an envelope of an input signal and generates an adaptive current-draw control signal.

67. A method for a variable power amplifier, comprising:

detecting an input signal at an input port of a variable power amplifier;

determining a feedback signal to adjust an output power level of the variable power amplifier to maintain linear operation;

generating a feedback signal in response to detection of the input signal; and

turning on at least one cell of the variable power amplifier in response to the feedback signal, the cell having switchable transistor banks.

68. A method as in claim 67, further comprising determining the feedback signal to adjust a linear operating range of the variable power amplifier.

69. A method as in claim 68, further comprising generating a bias current to selectively turn on at least one transistor bank.

70. A method as in claim 69, further comprising converting an input RF signal waveform to a detected voltage as the feedback signal.

71. A method as in claim 70, further comprising producing a control signal based on the detected voltage to adjust the output power level.

72. A method as in claim 69, further comprising:

controlling a peak output power level of the variable power amplifier.

73. The method as in claim 67, wherein the input signal is a wireless communication signal and the method further comprising:

amplifying the wireless communication signal; and

modulating the wireless communication signal.

74. The method as in claim 73, wherein modulating the wireless communication signal further comprises modulating the wireless communication signal according to a protocol selected from the group of:

Quadrature Amplitude Modulation (QAM), Orthogonal Frequency Divisional Multiple Access (OFDMA), Code Division-Multiple Access (CDMA), WiFi, Long Term Evolution (LTE), or WiMax.

75. The method as in claim 73, wherein the switchable transistor banks are fabricated using a technology selected from:

GaAs, pHEMT, SiGe HBT, or Si CMOS.

76. A system, comprising:

an input port to receive an analog signal;

switchable transistor banks to amplify the analog signal;

a control circuit coupled to the input port, wherein the control circuit generates a feedback control signal for the amplifier in response to a received analog signal; and

a bias control circuit coupled to the amplifier to selectively turn on the switchable transistor banks in response to the feedback control signal.

77. The system as in claim 76, wherein the switchable transistor banks further comprise a first transistor and a second transistor sharing a common source connection, a common drain connection, and common gate connection.

78. The system as in claim 76, wherein each of the switchable transistor banks has a same number of transistors.

79. The system as in claim 76, wherein a first transistor bank has a different number of transistors than a second transistor bank.

80. The system as in claim 76, wherein the system supports a plurality of frequency bands.

81. The system as in claim 76, further comprising an input matching network and an output matching network having a tuning capacitor and a switch connected in series.

82. The system as in claim 81, wherein the output matching network is structured as a non-switchable circuit.

83. The system as in claim 82, wherein the input matching network and the input matching network are each formed using conventional right-handed components, including a series inductor and a shunt capacitor.

84. The system as in claim 76, further comprising a second bias control circuit coupled to the control circuit to convert a received feedback control signal to a second control signal for control of the switchable transistor banks, wherein the bias control circuit and the second bias control circuit operate to provide variable control of the switchable transistor banks.

85. The system as in claim 76, further comprising:

a transmit module that provides analog signals to the input port.