Power amplifier
View Patent ↗A radio frequency power amplifier including control electronics for providing control signals for timing of the power amplifier. A first group of the drivers are coupled to the control electronics and a second group of drivers are coupled to the control electronics. The first group of drivers operate in response to the control signals to generate first drive signals and the second group of drivers operate in response to the control signals to generate second drive signals with a phase difference of 180° relative to the first drive signals. A first group of switches energize a first group of primary windings in response to the first drive signals and a second group of switches energize a second group of primary windings in response to the second drive signals. An output summing transformer has a plurality of ferrite cores, the first group of primary windings and the second group of primary windings passing through the ferrite cores. A secondary output winding for connection with a load passes through the ferrite cores of the output summing transformer.
1. A radio frequency power amplifier comprising:
a control electronics providing control signals for timing of the power amplifier;
a first group of drivers coupled to the control electronics and a second group of drivers coupled to the control electronics, the first group of drivers operating in response to the control signals to generate first drive signals, the second group of drivers operating in response to the control signals to generate second drive signals with a phase difference of 180° relative to the first drive signals;
a first group of switches energizing a first group of primary windings in response to the first drive signals;
a second group of switches energizing a second group of primary windings in response to the second drive signals;
an output-summing transformer having a plurality of ferrite cores, one primary winding of the first group of primary windings and one primary winding of the second group of primary windings passing through each of the plurality of ferrite cores, the first group of primary windings passing through the plurality of ferrite cores in a first direction and the second group of primary windings passing through the plurality of ferrite cores in a second direction opposite the first direction; and
a secondary output winding for connection with a load, the secondary output winding passing through the plurality of ferrite cores of the output-summing transformer.
2. The power amplifier of claim 1 further comprising:
a number of Q-damper transistors coupled to a secondary damping winding, the secondary damping winding passing through the ferrite cores for reducing the Q of the amplifier load between transmit pulses.
3. The power amplifier of claim 2 wherein the power amplifier operates in A, B, C, D, E, F and S modes.
4. The power amplifier of claim 1 wherein the first group of switches further comprises first transistors having a first terminal coupled to the first primary winding and a second terminal coupled to ground and the second group of switches further comprises second transistors having a first terminal coupled to the second primary winding and a second terminal coupled to ground.
5. The power amplifier of claim 4 wherein the first primary winding is coupled to a power supply and the second primary winding is coupled to the power supply.
6. The power amplifier of claim 4 wherein the first transistors have a gate terminal coupled to first transient voltage suppressors and the second transistors have a gate terminal coupled to second transient voltage suppressors.
7. The power amplifier of claim 1 wherein the signals from the different stages are delayed to compensate the propagation time of the signals in the output summing transformer.
8. The power amplifier of claim 1 wherein the ferrite cores are toroids, the first group of primary windings and the second group of primary windings passing through the toroid center in opposite directions.
9. An output summing transformer comprising:
ferrite cores, where a number of ferrite cores is equal to a number of the stages of a power amplifier;
a first group of primary windings passing through the ferrite cores and a second group of primary windings passing through the ferrite cores;
a secondary output winding passing through the ferrite cores for connection with a load;
a secondary damping winding passing through the ferrite cores; and
a number of Q-damper transistors coupled to the secondary damping winding for reducing the Q of the amplifier load between transmit pulses.
10. The output summing transformer of claim 9 wherein the first group of primary windings pass through the ferrite cores in a first direction and the second group of primary windings pass through the ferrite cores in a second direction opposite the first direction.
11. The output summing transformer of claim 9 wherein the ferrite cores are toroids, the first group of primary windings and the second group of primary windings passing through the toroid center in opposite directions.
12. The output summing transformer of claim 9 wherein windings in the first group of primary windings have a first terminal for connection to a power supply and a second terminal for connection to a first switch, windings in the second group of primary windings have a first terminal for connection to a power supply and a second terminal for connection to a second switch.
13. The output summing transformer of claim 9 wherein the secondary output winding has a shape of a coaxial cable, the secondary output winding including an outer cylindrical electrode connected by an end plate with a central electrode.
14. The output summing transformer of claim 13 wherein the central electrode passes through the ferrite cores.
15. The output summing transformer of claim 14 wherein connection to the load is made with the central electrode at an open end opposite the end plate.