Search

EP-4742529-A1 - DUAL POWER AMPLIFIER WITH TUNABLE OUTPUT COMBINER CIRCUIT

EP4742529A1EP 4742529 A1EP4742529 A1EP 4742529A1EP-4742529-A1

Abstract

A radio frequency amplifier device includes four power amplifiers. The first power amplifier output is coupled through a first inductive element to a first signal output terminal and through a second inductive element to a first shunt circuit access terminal. The second power amplifier output is coupled through a third inductive element to the first shunt circuit access terminal. The third power amplifier output is coupled through a fourth inductive element to a second signal output terminal and through a fifth inductive element to a second shunt circuit access terminal. The fourth power amplifier output is coupled through a sixth inductive element to the second shunt circuit access terminal. A first output combiner circuit includes the second and third inductive elements, and a second output combiner circuit includes the fifth and sixth inductive elements. External shunt capacitors are coupled to the first and second shunt circuit access terminals.

Inventors

  • DONG, YUANYUAN
  • SCATAMACCHIA, DAMIEN
  • CASSAN, CEDRIC

Assignees

  • NXP USA, Inc.

Dates

Publication Date
20260513
Application Date
20241112

Claims (15)

  1. A radio frequency amplifier device (322, 422, 422', 622, 722) comprising: a discrete package body (323, 423); a first signal output terminal (326, 426) and a second signal output terminal (326', 426') connected to the discrete package body; one or more first shunt circuit access terminals (327, 427, 527-1, 527-2) and one or more second shunt circuit access terminals (327', 427', 527-1', 527-2'), connected to the discrete package body; a first power amplifier (370, 470, 650, 750) connected to the discrete package body and including a first amplifier output (372, 472, 652, 752) electrically coupled through a first inductive element (356, 456, 656, 756) to the first signal output terminal and electrically coupled through a second inductive element (382, 482, 682, 782) to the one or more first shunt circuit access terminals (327, 427, 527-2); a second power amplifier (350, 450, 670, 770) connected to the discrete package body and including a second amplifier output (352, 452, 672, 772) electrically coupled through a third inductive element (381, 481, 681, 781) to the one or more first shunt circuit access terminals (327, 427, 527-1); a first output combiner circuit (380, 480, 680, 780) that includes the second and third inductive elements; a third power amplifier (370', 470', 650', 750') connected to the discrete package body and including a third amplifier output (372', 472', 652', 752') electrically coupled through a fourth inductive element (356', 456', 656', 756') to the second signal output terminal and electrically coupled through a fifth inductive element (382', 482', 682', 782') to the one or more second shunt circuit access terminals (327', 427', 527-2'); a fourth power amplifier (350', 450', 670', 770') connected to the discrete package body and including a fourth amplifier output (352', 452', 672', 772') electrically coupled through a sixth inductive element (381', 481', 681', 781') to the one or more second shunt circuit access terminals (327', 427', 527-1'); and a second output combiner circuit (380', 480', 680', 780') that includes the fifth and sixth inductive elements.
  2. The radio frequency amplifier device of claim 1, wherein: the one or more first shunt circuit access terminals consists of two first shunt circuit access terminals (527-1, 527-2), the first amplifier output is electrically coupled through the second inductive element to one of the two first shunt circuit access terminals, and the second amplifier output is electrically coupled through the third inductive element to another one of the two first shunt circuit access terminals.
  3. The radio frequency amplifier device of claim 1, wherein: the one or more first shunt circuit access terminals consists of a single first shunt circuit access terminal (327, 427, 627, 727), and both the first amplifier output and the second amplifier output are electrically coupled through the second and third inductive elements, respectively, to the single first shunt circuit access terminal.
  4. The radio frequency amplifier device of claim 3, wherein: the first amplifier output corresponds to a first combining node (386, 486) of the first output combiner circuit; and a first electrical length between the first amplifier output and the second amplifier output through the second and third inductive elements is about 90 degrees.
  5. The radio frequency amplifier device of claim 1, wherein: the first signal output terminal (326, 426) corresponds to a first combining node (686, 786) of the first output combiner circuit; the one or more first shunt circuit access terminals consists of a single first shunt circuit access terminal (327, 427); the second amplifier output is electrically connected through the third inductive element to the to the single first shunt circuit access terminal; and the second inductive element has a first end connected to the first signal output terminal and a second end connected to the single first shunt circuit access terminal.
  6. The radio frequency amplifier device of claim 5, wherein: a first electrical length between the second amplifier output and the first signal output terminal through the second and third inductive elements is about 180 degrees; and a second electrical length between the first amplifier output and the first signal output terminal through the first inductive element is about 90 degrees.
  7. The radio frequency amplifier device of any preceding claim, further comprising: a first amplifier input terminal (325, 425, 624, 724) and a second amplifier input terminal (324, 424, 625, 725) connected to the discrete package body, wherein a first amplifier input (371, 471, 651, 751) of the first power amplifier (370, 470, 650, 750) is electrically coupled to the first amplifier input terminal; and a second amplifier input (351, 451, 671, 771) of the second power amplifier (350, 450, 670, 770) is electrically coupled to the second amplifier input terminal.
  8. The radio frequency amplifier of claim 7, further comprising: a first impedance matching circuit (362, 632) that electrically couples the first amplifier input and the first amplifier input terminal; and a second impedance matching circuit (332, 662) that electrically couples the second amplifier input and the second amplifier input terminal.
  9. The radio frequency amplifier of any preceding claim, wherein: the first signal output terminal, the one or more first shunt circuit access terminals, the first power amplifier, the second power amplifier, the first, second, and third inductive elements, and the first output combiner circuit form portions of a first Doherty power amplifier (316, 416, 616, 716); and the second signal output terminal, the one or more second shunt circuit access terminals, the third power amplifier, the fourth power amplifier, the fourth, fifth, and sixth inductive elements, and the second output combiner circuit form portions of a second Doherty power amplifier (316', 416', 616', 716').
  10. A radio frequency transmitter (108, 208) comprising: the radio frequency amplifier device according to claim 1 a first transmitter substrate (101, 201, 301, 401); and a first amplifier (316, 316', 416, 416', 616, 616', 716, 716') coupled to the first transmitter substrate, wherein the first amplifier includes a transmitter input terminal (311, 411), a transmitter output terminal (392, 492), the radio frequency amplifier device is physically coupled to the first transmitter substrate, and further includes one or more first amplifier input terminals (324, 325, 424, 425, 624, 625, 724, 725) and one or more second amplifier input terminals (324', 325', 424', 425', 624', 625', 724', 725'), a first signal power splitter (312, 412) physically coupled to the first transmitter substrate and having a first splitter input terminal (313), a first splitter output terminal (314), and a second splitter output terminal (315), wherein the first splitter input terminal is electrically coupled to the transmitter input terminal (311, 411), the first splitter output terminal is electrically coupled to the one or more first amplifier input terminals, and the second splitter output terminal is electrically coupled to the one or more second amplifier input terminals, a first capacitor (383, 483) physically coupled to the first transmitter substrate and having a first capacitor terminal coupled to the one or more first shunt circuit access terminals (327, 427) and a second capacitor terminal coupled to a ground reference (385, 485) of the first transmitter substrate, a second capacitor (383', 483') physically coupled to the first transmitter substrate and having a third capacitor terminal coupled to the one or more second shunt circuit access terminals (327', 427') and a fourth capacitor terminal coupled to the ground reference of the first transmitter substrate, and a signal power combiner (388, 488) physically coupled to the first transmitter substrate and having a first combiner input terminal (389), a second combiner input terminal (390), and a combiner output terminal (391), wherein the first combiner input terminal is electrically coupled to the first signal output terminal (326, 426), and the second combiner input terminal is electrically coupled to the second signal output terminal (326', 426').
  11. The radio frequency transmitter of claim 10, wherein: the one or more first amplifier input terminals includes two first amplifier input terminals (324, 325, 424, 425, 624, 625, 724, 725); the one or more second amplifier input terminals includes two second amplifier input terminals (324', 325', 424', 425', 624', 625', 724', 725'); and the radio frequency transmitter further includes a second signal power splitter (317) physically coupled to the first transmitter substrate and having a second splitter input terminal (318), a third splitter output terminal (319), and a fourth splitter output terminal (320), wherein the second splitter input terminal is electrically coupled to the first splitter output terminal of the first signal power splitter, the third splitter output terminal is electrically coupled to one of the two first amplifier input terminals (324, 424, 624, 724), and the fourth splitter output terminal is electrically coupled to another one of the two first amplifier input terminals (325, 425, 625, 725), and a third signal power splitter (317') physically coupled to the first transmitter substrate and having a third splitter input terminal (318'), a fifth splitter output terminal (319'), and a sixth splitter output terminal (320'), wherein the third splitter input terminal is electrically coupled to the second splitter output terminal of the first signal power splitter, the fifth splitter output terminal is electrically coupled to one of the two second amplifier input terminals (324', 424', 624', 724'), and the sixth splitter output terminal is electrically coupled to another one of the two second amplifier input terminals (325', 425', 625', 725').
  12. The radio frequency transmitter of claim 11, wherein: the second signal power splitter, the two first amplifier input terminals, the first signal output terminal, the one or more first shunt circuit access terminals, the first power amplifier, the second power amplifier, the first, second, and third inductive elements, and the first output combiner circuit form portions of a first Doherty power amplifier (316, 416, 616, 716); and the third signal power splitter, the two second amplifier input terminals, the second signal output terminal, the one or more second shunt circuit access terminals, the third power amplifier, the fourth power amplifier, the fourth, fifth, and sixth inductive elements, and the second output combiner circuit form portions of a second Doherty power amplifier (316', 416', 616', 716').
  13. The radio frequency transmitter of any of claims 10 to 12, wherein: the first amplifier is a driver amplifier (110, 210) of the radio frequency transmitter (108, 208); and the radio frequency transmitter further includes a final-stage amplifier (190, 290) with a final-stage amplifier input electrically coupled to the combiner output terminal.
  14. The radio frequency transmitter of any of claims 10 to 13, wherein: the one or more first shunt circuit access terminals consists of a single first shunt circuit access terminal (327, 427), and both the first amplifier output and the second amplifier output are electrically coupled through the second and third inductive elements, respectively, to the single first shunt circuit access terminal.
  15. The radio frequency transmitter of any of claims 10 to 13, wherein: the one or more first shunt circuit access terminals consists of two first shunt circuit access terminals (527-1, 527-2), the first amplifier output is electrically coupled through the second inductive element to one of the two first shunt circuit access terminals (527-1), and the second amplifier output is electrically coupled through the third inductive element to another one of the two first shunt circuit access terminals (527-2); and the radio frequency transmitter further includes a first conductive path (584) coupled to the transmitter substrate and extending between the two first shunt circuit access terminals, wherein the first capacitor terminal of the first capacitor (483) is coupled to the first conductive path.

Description

TECHNICAL FIELD Embodiments of the subject matter described herein relate generally to power amplifiers, and particularly to power amplifiers implemented in cellular base station transmitters. BACKGROUND A cellular base station enables mobile devices to connect with a cellular network. To provide for two-way communications between the mobile devices and the network, a cellular base station may include multiple radio frequency (RF) transceivers, each of which includes a transmitter path (for transmitting signals from the network to the mobile devices) and a receiver path (for receiving signals from the mobile devices and providing the signals to the network). A transmitter path of a base station transceiver may include several gain stages (e.g., a pre-driver stage, a driver stage, and a final stage). The physical size of the transmitter path is governed, at least in part, by the design of the gain stages and associated circuitry and packaging (e.g., inter-stage isolators, impedance matching circuits, bias circuitry, heat dissipation structures, and so on). Because cellular base stations typically are deployed in the outside environment, there is a desire to minimize their size in order to make them less conspicuous. Accordingly, cellular communication system operators desire base stations (and thus base station transceivers) that are as small as possible, while still providing excellent performance. Operators specifically desire base station amplifiers that have smaller form factors, flexibility (e.g., designs that can easily be modified for different frequencies of operation), and low cost (e.g., reduced bill of material (BOM)), among other features. With ever present trends toward miniaturization, cost containment, and flexibility, what are needed are more compact cellular base stations, and particularly more compact base station transceivers and base station transmitters. BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the subject matter may be derived by referring to the detailed description and claims when considered in conjunction with the following figures, wherein like reference numbers refer to similar elements throughout the figures. FIG. 1 illustrates a cellular radio system that includes multiple transmitters, in accordance with an example embodiment;FIG. 2 is a schematic drawing of a radio frequency (RF) transmitter, in accordance with an example embodiment;FIG. 3 is a schematic drawing of an amplification stage that includes a dual 90/0 Doherty power amplifier with tunable output combiner circuits, in accordance with an example embodiment;FIG. 4 is a top view of an amplification stage that includes a dual 90/0 Doherty power amplifier with tunable output combiner circuits, in accordance with an example embodiment;FIG. 5 is a top view of an RF amplifier device for use in an amplification stage that includes a dual 90/0 Doherty power amplifier with a tunable output combiner circuit, in accordance with another example embodiment;FIG. 6 is a schematic drawing of an amplification stage that includes a dual 90/180 Doherty power amplifier with tunable output combiner circuits, in accordance with yet another example embodiment; andFIG. 7 is a top view of an amplification stage that includes a dual 90/180 Doherty power amplifier with tunable output combiner circuits, in accordance with yet another example embodiment. DETAILED DESCRIPTION Embodiments of the inventive subject matter include high performing radio frequency (RF) transmitters (e.g., for cellular base stations or other applications) and, more specifically, RF transmitters that are relatively compact and provide for flexibility (e.g., tunability for different operational frequencies). For example, embodiments of RF amplifiers are illustrated and described herein, which include dual Doherty power amplifiers with output combiner circuits that are integrated (e.g., packaged) in such a manner to provide for compactness, while also providing for frequency tunability. These RF amplifiers enable a cellular communications system operator to utilize the same overall transmitter design (e.g., the same transmitter PCB) for amplifiers that operate in different frequency bands by simply changing, on the transmitter PCB, the packaged RF amplifier device (e.g., device 322, 422, 522, 622, 722, FIGs 3-7) and the value of one or more discrete capacitors (e.g., capacitors 383, 383', 483, 483', FIGs 3-7), which are accessible outside of the packaged RF amplifier device. For example, one or more embodiments of RF amplifiers illustrated and described herein include RF amplifier devices that include multiple amplification paths (e.g., multiple amplification paths of a dual Doherty power amplifier) that are integrated into a same discrete package, along with output combiner circuits that combine the amplified output signals from the multiple amplification paths. As will be described in detail later, certain tuning points within the output combiner c