Radio frequency signal power amplifier combining network

• US 5,438,684 A
• Filed: 03/10/1994
• Issued: 08/01/1995
• Est. Priority Date: 03/13/1992
• Status: Expired due to Term

• Current Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Osmani, Rashid M., Schwent, Dale G., Weisshappel, Robert N.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Pham, Chi H.
• Application Number:
  US08/209,697
• Time in Patent Office: 509 Days
• Field of Search: 455/89, 455/93, 455/95, 455/102, 455/103, 455/116, 455/126, 455/127, 375/5, 330/51, 330/124 R, 330/126, 330/744, 330/295
• US Class Current: 455/552.1
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 1/0288 using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers
• CPC Class Codes: H03F 2200/432 Two or more amplifiers of different type are coupled in parallel at the input or output, e.g. a class D and a linear amplifier, a class B and a class A amplifier
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 2001/0408 with power amplifiers

Abstract

A dual-mode RF signal power amplifier combining network is comprised of two branches, each having a power amplifier (200 and 201). The first branch contains a non-linear mode power amplifier (200) while the second branch contains a linear mode power amplifier (201). The non-linear mode branch also has an RF switch (210). Both branches are coupled to a common output node (220). The common node (220) is coupled to a filter (107) before going to an antenna (106). The non-linear mode power amplifier (200) operates when an FM signal is to be amplified, while the linear amplifier (201) is biased in an off state. The linear mode power amplifier (201) operates when a digital signal is to be amplified, while the non-linear amplifier (200) is biased in an off state. The RF switch (210) removes the non-linear amplifier (200) from the circuit to prevent loading the on state linear amplifier (201).

Claims

1. A radio frequency (RF) signal power amplifier combining network responsive to a control signal for operation in a linear mode or a saturation mode, said RF signal power amplifier combining network comprising:

a first amplifier for amplifying a first RF signal in the linear mode;

a second amplifier for amplifying a second RF signal in the saturation mode, the second amplifier coupled to the first amplifier in an electrically parallel configuration;

first and second output transmission lines coupled to the first and second amplifiers, respectively;

a common node that couples the first and second output transmission lines; and

a switch in series with at least one of the first and second output transmission lines and responsive to the control signal for coupling or decoupling the corresponding one of the first and second amplifiers and the common node.

2. The RF signal power amplifier combining network of claim 1 wherein the switch is a PIN diode in series with the at least one of the first and second output transmission lines.

3. The RF signal power amplifier combining network of claim 1 and further including a second common node for combining inputs of the first and second amplifiers into a single input RF signal line.

4. The RF signal power amplifier combining network of claim 1 and further including first and second biasing means coupled to the first and second amplifiers, and being responsive to the control signal for coupling and decoupling different bias voltages to the first and second amplifiers.

5. The RF signal power amplifier combining network of claim 4 wherein the first RF signal is a differential quadrature phase shifted keying (DQPSK) modulated input RF signal, the second RF signal is a frequency modulated (FM) input RF signal, the first amplifier applies a gain greater than unity to a DQPSK modulated input RF signal, and the second amplifier applies a gain greater than unity to an FM input RF signal.

6. The RF signal power amplifier combining network of claim 1 wherein the first output transmission line is a 16°

transmission line and the second output transmission line is a 107°

transmission line.

7. The RF signal power amplifier combining network of claim 1 wherein the common node is coupled to an antenna that radiates the amplified RF signal from the first and second amplifiers.

8. A radio frequency (RF) signal power amplifier combining network responsive to a control signal for operation in a linear mode or a saturation mode, said RF signal power amplifier combining network comprising:

first and second RF signal input lines;

a first common node coupling the first and second RF signal input lines;

a first amplifier for amplifying a first RF signal, on the first RF input signal line, in a linear mode and a second amplifier in parallel with said first amplifier for amplifying a second RF signal, on the second RF input signal line, in a saturation mode;

a switch coupled to an output of the second amplifier;

a first output transmission line coupled to the first amplifier and a second output transmission line coupled to the switch, the switch responsive to the control signal for coupling or de-coupling the second amplifier and the second output transmission line; and

a second common node coupling the first and second output transmission lines.

9. A dual-mode radio frequency (RF) signal communications device comprising:

control means for producing a control signal for operation in a linear mode or a saturation mode;

a modulator for producing, in response to the control signal, a frequency modulated (FM) signal in the saturation mode and a time division multiple access (TDMA) signal in the linear mode;

a power amplifier combining network, coupled to the modulator, comprising;

a first amplifier for amplifying the TDMA signal;

a second amplifier for amplifying the FM signal, the second amplifier coupled to the first amplifier in an electrically parallel configuration;

a first and a second output transmission line coupled to the first and second amplifiers, respectively;

a common node coupling the first and second output transmission lines; and

a switch coupled in series with one of the first or second output transmission lines and responsive to the control signal for coupling or decoupling the corresponding one of the first or second amplifiers to the common node; and

an antenna coupled to the common node.