Power amplifier circuit and method for envelope modulation of high frequency signal

• US 20080008273A1
• Filed: 02/07/2007
• Published: 01/10/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Seung Woo, Lee, Jeong Hoon, Lee, Jae Sup
• Granted Patent: US 7,616,053 B2
• Time in Patent Office: Days
• US Class Current: 375/346
• CPC Class Codes: H03C 1/36 by means of semiconductor device having at least three electrodes H03C1/34, H03C1/50, H03C1/52, H03C1/62 take precedence
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/0261 with control of the polarisation voltage or current, e.g. gliding Class A
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• CPC Class Codes: H03F 2200/18 the bias of the gate of a FET being controlled by a control signal
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit
• 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 2200/408 the output amplifying stage of an amplifier comprising three power stages
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/541 Transformer coupled at the output of an amplifier
• CPC Class Codes: H03F 3/24 of transmitter output stages

Abstract

A power amplifier circuit includes: a transformer receiving a first signal and generating a transformed signal from the first signal; and a transistor receiving a second signal having a direct current (DC) component, and generating an output signal. The second signal and the transformed signal are mixed, via a terminal connected with the transformed signal, wherein an envelope of the output signal is controlled by the first signal.

Claims

1. A power amplifier circuit comprising:

a transformer which receives a first signal and generates a transformed signal from the first signal; and

a transistor which receives a second signal having a direct current (DC) component, and generates an output signal corresponding to a mixture of the second signal and the transformed signal, via a terminal connected with the transformed signal,

wherein an envelope of the output signal is controlled by the first signal.

2. The power amplifier circuit of claim 1, wherein, two terminals of a first coil of the transformer respectively receive a first power source and the first signal, a first terminal of a second coil of the transformer is connected with a second power source, and a second terminal of the second coil generates the transformed signal.

3. The power amplifier circuit of claim 2, wherein, a gate of the transistor receives the second signal, a first terminal among a drain and a source of the transistor is connected with the transformed signal, a second terminal among the drain and the source is connected with the first power source, and the first terminal generates the output signal.

4. The power amplifier circuit of claim 1, further comprising:

an envelope shaper which generates the first signal by low pass filtering and amplifying an input analog signal.

5. The power amplifier circuit of claim 1, further comprising:

a bias circuit which generates at least one DC component from a power source; and

a driver stage which generates the second signal from an input analog signal using at least one amplifier biased by the at least one DC component.

6. The power amplifier circuit of claim 5, wherein the bias circuit comprises:

a second transformer which receives the first signal and generates a second transformed signal from the first signal,

wherein the second signal corresponds to a mixture of the second transformed signal and an analog signal having the DC component.

7. The power amplifier circuit of claim 1, further comprising:

an impedance matching circuit connected with the output signal.

8. A power amplifier circuit comprising:

a first transformer which receives a first signal and generates a first transformed signal from the first signal;

a first transistor which receives a second signal having a DC component, and generates a first output signal corresponding to a mixture of the second signal and the first transformed signal, via a terminal connected with the first transformed signal;

a second transformer which receives a third signal and generates a second transformed signal from the third signal; and

a second transistor which receives a fourth signal having the DC component, and generates a second output signal corresponding to a mixture of the fourth signal and the second transformed signal, via a terminal connected with the second transformed signal,

wherein the power amplifier circuit generates a signal that corresponds to a mixture of the first output signal and the second output signal.

9. The power amplifier circuit of claim 8, wherein a phase difference between the first signal and the third signal is 90 degrees, and a phase difference between the second signal and the fourth signal is 270 degrees.

10. The power amplifier circuit of claim 8, further comprising:

a third transformer which receives the first signal and generates a third transformed signal from the first signal; and

a fourth transformer which receives the third signal and generates a fourth transformed signal from the third signal,

wherein the second signal corresponds to a mixture of an analog signal having the DC component, and the second transformed signal, and

the fourth signal corresponds to a mixture of the analog signal and the fourth transformed signal.

11. A power amplifier circuit comprising:

a transformer which receives a pair of differential signals and generates a transformed signal from the pair of differential signals; and

a transistor which receives a second signal having a DC component, and generates an output signal which corresponds to a mixture of the second signal and the transformed signal, said mixture being mixed via a terminal connected with the transformed signal,

wherein an envelope of the output signal is controlled by the differential signals.

12. The power amplifier circuit of claim 11, wherein, two terminals of a first coil of the transformer respectively receive a first differential signal and a second differential signal, said first differential signal and said second differential signal have a 180 degree phase difference from each other, a first terminal of a second coil of the transformer is connected with a second power source, and a second terminal of the second coil generates the transformed signal.

13. The power amplifier circuit of claim 12, further comprising:

a first pulse width modulator which generates the first differential signal from a first analog signal of the pair of analog differential signals; and

a second pulse width modulator which generates the second differential signal from a second analog signal of the pair of analog differential signals.

14. The power amplifier circuit of claim 11, further comprising:

a second transformer which receives the pair of differential signals and generates a second transformed signal from the pair of differential signals,

wherein the second signal corresponds to a mixture of an analog signal having the DC component and the second transformed signal.

15. The power amplifier circuit according to claim 11, wherein the transistor is an N channel metal-oxide semiconductor field effect transistor (MOSFET).

16. The power amplifier circuit according to claim 11, wherein the amplifier circuit is utilized for a transmitter of a wireless communication system.

17. A signal amplification method comprising:

receiving a first signal to generate a transformed signal, by a transformer;

receiving a second signal having a DC component, by a transistor; and

generating an output signal corresponding to a mixture of the second signal and the transformed signal, via a terminal connected with the transformed signal, by the transistor,

wherein an envelope of the output signal is controlled by the first signal.

18. A signal amplification method comprising:

receiving a first signal to generate a first transformed signal, by a first transformer;

receiving a second signal having a DC component, by a first transistor;

generating a first output signal corresponding to a mixture of the second signal and the first transformed signal, via a terminal connected with the first transformed signal, in the first transistor;

receiving a third signal to generate a second transformed signal, by a second transformer;

receiving a fourth signal having the DC component, by a second transistor;

generating a second output signal corresponding to a mixture of the fourth signal and the second transformed signal, via a terminal connected with the second transformed signal, by the second transistor; and

generating a signal that corresponds to a mixture of the first output signal and the second output signal.

19. A signal amplification method comprising:

receiving a first analog signal and a second analog signal that are a pair of analog differential signals;

generating a first pulse width modulated signal from the first analog signal;

generating a second pulse width modulated signal from the second analog signal;

receiving the first pulse width modulated signal and the second pulse width modulated signal via a first coil of a transformer and generating a transformed signal from a second coil of the transformer;

receiving a signal having a DC component, by a transistor; and

generating an output signal corresponding to a mixture of the signal having the DC component and the transformed signal, via a terminal connected with the transformed signal, by the transistor,

wherein an envelope of the output signal is controlled by the pair of analog differential signals.