High efficiency amplifier

• US 20040189380A1
• Filed: 03/28/2003
• Published: 09/30/2004
• Est. Priority Date: 03/28/2003
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew Corporation (CommScope Holding Company, Inc.)
• Inventors: Louis, Edward Vincent, Root, Loren Francis, Loh, Koon Whye, Myer, Robert E.
• Granted Patent: US 6,922,102 B2
• Time in Patent Office: Days
• US Class Current: 330/124R
• CPC Class Codes: H03F 1/0266 by using a signal derived from the input signal
• 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 2200/18 the bias of the gate of a FET being controlled by a control signal
• CPC Class Codes: H03F 2200/198 A hybrid coupler being used as coupling circuit between stages of an amplifier circuit
• CPC Class Codes: H03F 3/602 Combinations of several amplifiers

Abstract

An amplifier includes a main amplifier circuit and at least one auxiliary amplifier circuit. Portions of an RF signal to be amplified are delivered to the main and auxiliary amplifiers. The auxiliary amplifier circuit is selectively operable to operate in combination with the main amplifier circuit, such as based on the level of the RF signal. At least one hybrid coupler circuit has input ports coupled with outputs of the main amplifier circuit and auxiliary amplifier circuit. The hybrid coupler circuit is operable to combine amplifier circuit output signals at a coupler first output port. A coupler second output port is terminated with one of an electrical short and an electrical open circuit.

Claims

1. An amplifier comprising:

a main amplifier circuit;

at least one auxiliary amplifier circuit, the auxiliary amplifier circuit being selectively operable to operate in combination with the main amplifier circuit;

at least one hybrid coupler circuit having input ports coupled with outputs of the main amplifier circuit and auxiliary amplifier circuit and operable to combine amplifier circuit output signals at a coupler first output port;

a coupler second output port terminated with one of an electrical short and an electrical open circuit.

2. The amplifier of claim 1 further comprising a tuned segment of a transmission line coupled to the coupler second output port, the transmission line segment being tuned to present one of an electrical short and an electrical open circuit to the second output port.

3. The amplifier of claim 1 wherein the auxiliary amplifier circuit presents an effective high output impedance to an input port of the hybrid coupler.

4. The amplifier of claim 1 wherein the auxiliary amplifier circuit presents an effective low output impedance to an input port of the hybrid coupler.

5. The amplifier of claim 3 further comprising a phasing line which acts in conjunction with the auxiliary amplifier circuit to reflect a high output impedance to an input port of the hybrid coupler.

6. The amplifier of claim 4 further comprising a phasing line which acts in conjunction with the auxiliary amplifier circuit to reflect a low output impedance to an input port of the hybrid coupler.

7. The amplifier of claim 1 further comprising a gate control circuit coupled to the auxiliary amplifier circuit to selectively operate the auxiliary amplifier circuit.

8. The amplifier of claim 7 wherein said gate control circuit is operable to control turn ON characteristics of the operating auxiliary amplifier circuit.

9. The amplifier of claim 7 further comprising a detector operable to detect a level of an input signal to the amplifier, the gate control circuit being coupled to the detector and selectively operating the auxiliary amplifier circuit based upon an input signal level.

10. The amplifier of claim 9 further comprising an attenuator coupled to the detector for affecting the level of the input signal detected by the detector.

11. The amplifier of claim 1 wherein said main and auxiliary amplifier circuits have generally equal power output capabilities.

12. The amplifier of claim 11 wherein the hybrid coupler is a −

3 dB coupler.

13. The amplifier of claim 1 wherein said main and auxiliary amplifier circuits have generally unequal power output capabilities.

14. The amplifier of claim 13 wherein the hybrid coupler has a coupling value reflective of the generally unequal power output capabilities of the amplifier circuits.

15. The amplifier of claim 1 further comprising a splitting coupler circuit coupled to inputs of the main and auxiliary amplifier circuits and operable for splitting an input signal to direct signals into the main and auxiliary amplifier circuits.

16. An amplifier comprising:

a main amplifier circuit;

a plurality of auxiliary amplifier circuits, the auxiliary amplifier circuits being selectively operable to operate in combination with the main amplifier circuit;

a first hybrid coupler circuit having input ports coupled to receive output signals from the main amplifier circuit and from the auxiliary amplifier circuits and operable to the combine main and auxiliary amplifier circuit output signals at a coupler first output port;

a coupler second output port terminated with one of an electrical short and an electrical open circuit.

17. The amplifier of claim 16 further comprising:

a second hybrid coupler circuit having input ports coupled to receive output signals from at least two auxiliary amplifier circuits, and operable to combine the auxiliary amplifier output signals at a first output port of the second hybrid coupler circuit;

a second output port of the second hybrid coupler circuit terminated with one of an electrical short and an electrical open circuit.

18. The amplifier of claim 17 wherein the first output port of the second hybrid coupler output circuit is coupled to an input port of the first hybrid coupler circuit to provide the output signals from the auxiliary amplifier circuits.

19. The amplifier of claim 16 further comprising a tuned segment of a transmission line coupled to the coupler second output port, the transmission line segment being tuned to present one of an electrical short and an electrical open circuit to the second output port.

20. The amplifier of claim 16 wherein the auxiliary amplifier circuit presents an effective high output impedance to an input port of the hybrid coupler.

21. The amplifier of claim 16 wherein the auxiliary amplifier circuit presents an effective low output impedance to an input port of the hybrid coupler.

22. The amplifier of claim 20 further comprising a phasing line which acts in conjunction with the auxiliary amplifier circuit to reflect a high output impedance to an input port of the hybrid coupler.

23. The amplifier of claim 21 further comprising a phasing line which acts in conjunction with the auxiliary amplifier circuit to reflect a low output impedance to an input port of the hybrid coupler.

24. The amplifier of claim 16 further comprising a gate control circuit coupled to the auxiliary amplifier circuits to selectively operate the auxiliary amplifier circuits.

25. The amplifier of claim 24 wherein said gate control circuit is operable to control turn ON characteristics of the operating auxiliary amplifier circuit.

26. The amplifier of claim 24 further comprising a detector operable to detect a level of an input signal to the amplifier, the gate control circuit being coupled to the detector and selectively operating the auxiliary amplifier circuit based upon an input signal level.

27. The amplifier of claim 26 further comprising an attenuator coupled to the detector for affecting the level of the input signal detected by the detector.

28. The amplifier of claim 16 wherein said main and auxiliary amplifier circuits have generally equal power output capabilities.

29. The amplifier of claim 16 wherein said main and auxiliary amplifier circuits have generally unequal power output capabilities.

30. The amplifier of claim 16 further comprising at least one splitting coupler circuit coupled to inputs of the main and auxiliary amplifier circuits and operable for splitting an input signal to the splitting coupler circuit to direct signals into the main and auxiliary amplifier circuits.

31. The amplifier of claim 16 further comprising a plurality of hybrid coupler circuits coupled to receive output signals from the main and auxiliary amplifier circuits in a corporate combiner arrangement for combining amplifier circuit output signals to form an output for the amplifier.

32. The amplifier of claim 16 further comprising a plurality of hybrid coupler circuits coupled to receive output signals from the main and auxiliary amplifier circuits in a serial combiner arrangement for combining amplifier circuit output signals to form an output for the amplifier.

33. The amplifier of claim 30 wherein said splitting coupler circuit includes a plurality of coupler circuits arranged in one of a corporate and serial arrangement.

34. The amplifier of claim 31 wherein the coupler circuits have generally the same coupler values.

35. The amplifier of claim 32 wherein the coupler circuits have different coupler values.