Switched-mode power amplifier integrally performing power combining
View Patent ↗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).
1. A switched-mode power amplifier configured for integrally amplifying and combining a plurality of analog phase modulated signals input thereto, said amplifier comprising:
(a) an input component for each of said plurality of analog phase modulated input signals wherein each said input component comprises at least one active device configured to be alternately switched by-said by an analog phase modulated input signal to present an amplified signal corresponding to said analog phase modulated 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;
wherein said impedance inverter comprises a lumped element equivalent component to a quarter-wavelength transmission line:
wherein said lumped element equivalent component comprises two or more of a series inductor, a series negative inductor, a shunt-to-ground inductor, a shunt-to-ground negative inductor, a series capacitor, a series negative capacitor, a shunt-to-ground capacitor, and a shunt-to-ground negative capacitor.
2. A switched-mode power amplifier according claim 1 ,
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.
3. A switched-mode power amplifier according to claim 1 ,
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.
4. A switched-mode power amplifier according to claim 1 ,
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.
5. A switched-mode power amplifier according to claim 1 ,
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.
6. A method for integrally amplifying and combining a plurality of analog phase modulated input signals to produce a single amplified, summation signal for input to a resonator component, said method comprising:
a. amplifying each said analog phase modulated input signal by a separate amplifier input component to produce an amplified signal corresponding to an analog phase modulated input signal and constituting a low output impedance voltage source, said amplifying comprising applying said analog phase modulated 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;
wherein said transforming is performed by an impedance inverter comprising a lumped element equivalent component to a quarter-wavelength transmission line; and
wherein said lumped element equivalent component comprises two or more of a series inductor, a series negative inductor, a shunt-to-ground inductor, a shunt-to-around negative inductor, a series capacitor, a series negative capacitor, a shunt-to-ground capacitor, and a shunt-to-around negative capacitor.
7. A method according to claim 6 , 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.
8. A method according to claim 6 , 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.
9. A method according to claim 6 , 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.
10. A method according to claim 6 , 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.
11. 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;
(d) an output resonator component; and,
(e) 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;
wherein said impedance inverter comprises at least one of:
(i) 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;
(iii) two series negative inductors and a shunt-to-ground inductor between said series inductor, said inductors being of equal absolute value;
(ii) 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; and
(iv) two series negative capacitors and a shunt-to-ground capacitor between said series capacitor, said capacitors being of equal absolute value.