Reduced power amplifier size through elimination of matching network

• US 10,084,411 B2
• Filed: 09/29/2015
• Issued: 09/25/2018
• Est. Priority Date: 02/15/2015
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Lehtola, Philip John
• Primary Examiner(s): Sorowar, Golam
• Application Number:
  US14/869,953
• Publication Number:
  US 20160241205A1
• Time in Patent Office: 1,092 Days
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/0227 using supply converters
• 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 1/565 using inductive elements
• 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 2200/171 A filter circuit coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2203/21109 An input signal being distributed by switching to a plurality of paralleled power amplifiers
• CPC Class Codes: H03F 2203/21157 A filter circuit being added at the output of a power amplifier stage
• CPC Class Codes: H03F 2203/7209 the gated amplifier being switched from a first band to a second band
• CPC Class Codes: H03F 3/191 Tuned amplifiers H03F3/193, H03F3/195 take precedence
• 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: 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 2001/0408 with power amplifiers

Abstract

Reduced power amplifier size through elimination of matching network. In some embodiments, a power amplification system can include a power amplifier (PA) configured to receive and amplify a radio-frequency (RF) signal. The power amplification system can further include a filter coupled to the PA and configured to condition the amplified RF signal. The PA can be further configured to drive approximately a characteristic load impedance of the filter. Such a configuration of the PA can be achieved by operating the PA with a high-voltage supply. Such a power amplification system can allow elimination of a matching network to, for example, reduce loss and device size.

Claims

1. A power amplification system comprising:

a plurality of power amplifiers, each configured to amplify a signal in a respective frequency band in an average power tracking mode; and

an output filter coupled to each power amplifier and having a load impedance, each power amplifier configured to be operated with a high voltage to provide an impedance that is approximately the same as the load impedance of the respective output filter, such that the power amplification system with the power amplifiers operated with the respective high voltages has a lower loss compared to another power amplification system having similar band handling capability but in which power amplifiers are operated with respective low voltages.

2. The power amplification system of claim 1 wherein the impedance of each power amplifier has a value greater than approximately 40 Ohms.

3. The power amplification system of claim 2 wherein the impedance of each power amplifier has a value of approximately 50 Ohms.

4. The power amplification system of claim 1 further comprising a supply system configured to provide the respective high voltage to each power amplifier.

5. The power amplification system of claim 4 wherein the supply system includes a boost DC/DC converter configured to generate the high-voltage based on a battery voltage Vbatt.

6. The power amplification system of claim 1 wherein each power amplifier includes a heterojunction bipolar transistor implemented as a gallium arsenide device.

7. The power amplification system of claim 6 wherein the high voltage is provided to a collector of the heterojunction bipolar transistor as a supply voltage.

8. The power amplification system of claim 1 wherein each output filter is a transmit filter configured to operate in a corresponding transmit frequency band.

9. The power amplification system of claim 8 wherein the transmit filter is part of a duplexer configured to operate in the transmit frequency band and a corresponding receive frequency band.

10. The power amplification system of claim 1 wherein each output filter is coupled to the respective power amplifier by an output path that is substantially free of an impedance transformation circuit.

11. The power amplification system of claim 1 wherein the power amplification system is substantially free of a band selection switch between the power amplifiers and their corresponding output filters.

12. The power amplification system of claim 1 wherein the high voltages provided to the respective power amplifiers have substantially the same value.

13. The power amplification system of claim 1 wherein the other power amplifier system is an envelope tracking power amplification system.

14. A wireless device comprising:

a transceiver;

a front-end module in communication with the transceiver and including a power amplification system having a plurality of power amplifiers, each configured to amplify a signal in a respective frequency band in an average power tracking mode, the power amplification system further including an output filter coupled to each power amplifier and having a load impedance, each power amplifier configured to be operated with a high voltage to provide an impedance that is approximately the same as the load impedance of the respective output filter, such that the power amplification system with the power amplifiers operated with the respective high voltages has a lower loss compared to another power amplification system having similar band handling capability but in which power amplifiers are operated with respective low voltages; and

an antenna in communication with the front-end module and configured to transmit the amplified signal associated with each of one or more of the power amplifiers.

15. A method for processing a signal, the method comprising:

amplifying the signal with a selected one of a plurality of power amplifiers each configured to operate in an average power tracking mode;

filtering the amplified signal with a selected one of output filters corresponding to the plurality of power amplifiers, each output filter having a load impedance; and

operating the selected power amplifier with a high voltage such that the power amplifier provides an impedance that is approximately the same as the load impedance of the respective output filter, such that the amplifying of the signal with the selected power amplifier operated with the respective high voltage results in a lower loss compared to amplifying of a signal with a selected one of similar power amplifiers having similar band handling capability but in which the selected power amplifier is operated with a low voltage.