Switched-mode power amplifier integrally performing power combining

• US 20040027199A1
• Filed: 06/30/2003
• Published: 02/12/2004
• Est. Priority Date: 12/03/2001
• Status: Active Grant

• Current Assignee: Zarbana Digital Fund LLC (Intellectual Ventures LLC)
• Original Assignee: Seven Generations Energy Ltd.
• Inventors: Wight, James Stuart, Grundlingh, Johan M.
• Granted Patent: US 6,937,096 B2
• Time in Patent Office: Days
• US Class Current: 330/251
• CPC Class Codes: H03F 2200/537 A transformer being used as coupling element between two amplifying stages
• CPC Class Codes: H03F 2200/541 Transformer coupled at the output of an amplifier
• CPC Class Codes: H03F 2203/21157 A filter circuit being added at the output of a power amplifier stage
• CPC Class Codes: H03F 2203/21172 A series resonance circuit being coupled at the output of a power amplifier
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/2173 of the bridge type
• CPC Class Codes: H03F 3/2178 using more than one switch or switching amplifier in parallel or in series H03F3/2173, H03F3/2175 take precedence

Abstract

A switched-mode power amplifier is configured for performing power amplification of a plurality of signals input thereto and integrally summing (combining) those signals. Conceptually, this is achieved by replacing the input winding of the transformer component of a transformer-coupled voltage switching amplifier with separate input components, one for each input signal, in similar manner to the configuration of the input components of a three-port combiner (trifilar). In a first transformer-containing category of embodiments of the invention, the input winding of the amplifier'"'"'s transformer is comprised of a plurality of series-coupled windings, one for each of the plurality of input components/signals such that the input components constitute a series connection of low output impedance sources applied to the amplifier'"'"'s resonator and load. This, in turn, provides a high level of isolation between the amplifier input components and results in a low level of loss. In a second non-transformer-containing category of embodiments of the invention, the transformer component is replaced by a transmission line impedance transformer, or a lumped element equivalent circuit, which transforms the low output impedance sources to high output impedance sources and those sources are connected in parallel (rather than in series per the first category of embodiments).

Claims

1. A switched-mode power amplifier configured for integrally amplifying and combining a plurality of signals input thereto, said amplifier comprising:

(a) an input component for each of said plurality of input signals wherein each said input component comprises at least one active device configured to be alternately switched by said input signal to present an amplified signal corresponding to said input signal, said amplified signal constituting a low output impedance voltage source;

(b) an output resonator component; and

,

(c) an impedance inverter between each said input component and said resonator component, said impedance inverter configured for transforming said low output impedance voltage source to a high output impedance current source, wherein said high output impedance sources are combined in parallel before being passed to said resonator component.

2. A switched-mode power amplifier according to claim 1 wherein said signals are analog phase modulated signals.

3. A switched-mode power amplifier according to claim 2 wherein said amplifier is one of class D, E or F.

4. A switched-mode power amplifier according to claim 3 wherein said amplifier is balanced.

5. A switched-mode power amplifier according to claim 3 wherein said amplifier is unbalanced.

6. A switched-mode power amplifier according to claim 2 wherein said impedance inverter is a quarter-wavelength (λ

/4) transmission line.

7. A switched-mode power amplifier according to claim 2 wherein said impedance inverter is a lumped element equivalent component to quarter-wavelength (λ

/4) transmission line.

8. A switched-mode power amplifier according to claim 7 wherein said lumped element equivalent component comprises a series inductor and two shunt-to-ground, negative inductors connected to each terminal end of said series inductor, said inductors being of equal absolute value.

9. A switched-mode power amplifier according to claim 7 wherein said lumped element equivalent component comprises two series negative inductors and a shunt-to-ground inductor between said series inductor, said inductors being of equal absolute value.

10. A switched-mode power amplifier according to claim 7 wherein said lumped element equivalent component comprises a series capacitor and two shunt-to-ground, negative capacitors connected to each terminal end of said series capacitor, said capacitors being of equal absolute value.

11. A switched-mode power amplifier according to claim 7 wherein said lumped element equivalent component comprises two series negative capacitors and a shunt-to-ground capacitor between said series capacitor, said capacitors being of equal absolute value.

12. A method for integrally amplifying and combining a plurality of input signals to produce a single amplified, summation signal for input to a resonator component, said method comprising:

(a) amplifying each said input signal by a separate amplifier input component to produce an amplified signal corresponding to said input signal and constituting a low output impedance voltage source, said amplifying comprising applying said input signal to at least one active device of said input component to cause alternate switching of said active device; and

,

(b) transforming each said low output impedance voltage source to a high output impedance current source; and

,

(c) combining said high output impedance sources in parallel to produce a single amplified, summation signal.

13. A method according to claim 12 whereby said signals are analog phase modulated signals.

14. A method according to claim 13 whereby said transforming is performed by an impedance inverter.

15. A method according to claim 14 whereby said impedance inverter is a quarter-wavelength (λ

/4) transmission line.

16. A method according to claim 14 whereby said impedance inverter is a lumped element equivalent component to a quarter-wavelength (λ

/4) transmission line.

17. A method according to claim 16 whereby said lumped element equivalent component comprises a series inductor and two shunt-to-ground, negative inductors of equal absolute value connected to each terminal end of said series inductance.

18. A method according to claim 16 whereby said lumped element equivalent component comprises two series negative inductors and a shunt-to-ground inductor between said series inductor, said inductors being of equal absolute value.

19. A method according to claim 16 whereby said lumped element equivalent component comprises a series capacitor and two shunt-to-ground, negative capacitors connected to each terminal end of said series capacitor, said capacitors being of equal absolute value.

20. A method according to claim 16 whereby said lumped element equivalent component comprises two series negative capacitors and a shunt-to-ground capacitor between said series capacitor, said capacitors being of equal absolute value.