Transmitter using input modulation for envelope restoration scheme for linear high-efficiency power amplification

• US 6,380,802 B1
• Filed: 12/29/2000
• Issued: 04/30/2002
• Est. Priority Date: 12/29/2000
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Camp, William O. Jr., Montalvo, Antonio J., Pehike, David R.
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): Nguyen, Patricia T.
• Application Number:
  US09/752,417
• Time in Patent Office: 487 Days
• Field of Search: 330/10, 330/136, 330/207.A, 330/207.P, 330/251, 330/298
• US Class Current: 330/10
• CPC Class Codes: H03C 5/00 Amplitude modulation and angle modulation produced simultaneously or at will by the same modulating signal H03C7/00 takes precedence
• CPC Class Codes: H03F 1/02 Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 3/2176 Class E amplifiers
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03F 3/393 with field-effect devices
• CPC Class Codes: H04B 2001/0408 with power amplifiers
• CPC Class Codes: H04B 2001/045 with means for improving efficiency

Abstract

An apparatus and method for creating an amplifier input waveform based on received phase and amplitude information from an input signal. The apparatus includes a first switch receiving phase information from a primary waveform and a second switch in communication with the first switch and the input. The second switch receives amplitude information from the primary waveform and receives the phase information from the first switch and uses the amplitude information to modulate the phase information. A secondary waveform is thus created for input to the amplifier load matching network. In this way, an amplitude modulated waveform is amplified at high efficiency, enabling application of either all or part of the phase and/or amplitude modulation at the input of the amplifier.

Claims

1. A switching circuit for providing a waveform for input into a load matching network in a “

class E”

amplifier, said circuit comprising;

a first switch receiving phase information from a primary waveform;

a second switch in communication with said first switch and said input and receiving amplitude information from said primary waveform; and

wherein said second switch receives said phase information from said first switch and uses said amplitude information to modulate said phase information to create a secondary waveform for input to said matching network.

2. The circuit of claim 1 wherein said secondary waveform is an approximation of said primary waveform.

3. The circuit of claim 1 wherein said first and second switches are transistors each having a gate, said first switch receives said phase information at its gate, and said second switch receives said amplitude information at its gate.

4. The circuit of claim 1 further comprising a digital signal processing device in communication with said second switch, wherein said digital signal processing device adjusts said amplitude information before it is received into said second switch to correct for distortion in said amplitude information.

5. The circuit of claim 1 further comprising:

a digital signal processing device in communication with said second switch; and

a feedback loop for sensing VSWR reflection from an antenna in communication with said amplifier, said feedback loop in communication with said digital signal processing device;

wherein said digital signal processing device adjusts said amplitude information before it is received into said second switch to correct for said VSWR reflection.

6. A switching circuit for providing a waveform for input into the load matching network in a “

class E”

amplifier, said circuit comprising;

a first switch receiving amplitude information from a primary waveform;

a second switch in communication with said first switch and said input and receiving phase information from a primary waveform; and

wherein said second switch receives said amplitude information from said first switch and uses said phase information to modulate said amplitude information to create a secondary waveform for input to said matching network.

7. The circuit of claim 6, wherein said secondary waveform is an approximation of said primary waveform.

8. The circuit of claim 6 wherein said first and second switches are transistors each having a gate, said first switch receives said amplitude information at its gate, and said second switch receives said phase information at its gate.

9. The circuit of claim 6 further comprising a digital signal processing device in communication with said first switch, wherein said digital signal processing device adjusts said amplitude information before it is received into said first switch to correct for distortion in said amplitude information.

10. The circuit of claim 6 further comprising:

a digital signal processing device in communication with said second switch; and

a feedback loop for sensing VSWR reflection from an antenna in communication with said amplifier, said feedback loop in communication with said digital signal processing device;

wherein said digital signal processing device adjusts said amplitude information before it is receive by said first switch to correct for said VSWR reflection.

11. A method for providing a waveform for input to the load matching network of a “

class E”

amplifier, said method comprising the steps of;

separating amplitude information and phase information from a primary waveform;

receiving said phase information into a first switch;

passing said phase information from said first switch to a second switch;

receiving said amplitude information into said second switch;

modulating said phase information with said second switch to create a secondary waveform; and

providing said secondary waveform as an input to said matching network.

12. A method for providing a waveform for input to the load matching network of a “

class E”

amplifier, said method comprising the steps of;

separating phase and amplitude information from a primary waveform;

controlling an electric current through a first switch in accordance with said phase information to provide a first switched output;

passing said first switched output from said first switch to a second switch;

controlling said first switched output through said second switch in accordance with said amplitude information to create a second switched output;

outputting said second switched output from said second switch to create a secondary waveform; and

providing said secondary waveform as an input to said matching network.

13. The method of claim 12 wherein said secondary waveform is an approximation of said primary waveform.

14. The method of claim 12 wherein said first and second switches are transistors each having a gate, said first switch receives said phase information at its gate to control said electric current through said first switch, and said second switch receives said amplitude information at its gate to control said first switched output through said second switch.

15. The method of claim 12 further comprising the step of adjusting said amplitude information before controlling said first switched output through said second switch to correct for distortion in said amplitude information.

16. The method of claim 12 further comprising the step of:

sensing VSWR reflection from an antenna in communication with said amplifier; and

adjusting said amplitude information before controlling said first switched output through said second switch to correct for said VSWR reflection.

17. A method for providing a waveform for input to the load matching network of a “

class E”

amplifier, said method comprising the steps of;

separating phase and amplitude information from a primary waveform;

controlling an electric current through a first switch in accordance with said amplitude information to provide a first switched output;

passing said first switch ed output from said first switch to a second switch;

controlling said first switched output through said second switch in accordance with said phase information to create a second switched output;

outputting said second switched output from said second switch to create a secondary waveform; and

providing said secondary waveform as an input to said matching network.

18. The method of claim 17 wherein said secondary waveform is an approximation of said primary waveform.

19. The method of claim 17 wherein said first and second switches are transistors each having a gate, said first switch receives said amplitude information at its gate to control said electric current through said first switch, and said second switch receives said phase information at its gate to control said first switched output through said second switch.

20. The method of claim 17 further comprising the step of adjusting said amplitude information before controlling electric current through said first switch to correct for distortion in said amplitude information.

21. The method of claim 17 further comprising the step of:

sensing VSWR reflection from an antenna in communication with said amplifier; and

adjusting said amplitude information before controlling electric current through said first switch to correct for distortion in said amplitude information.