Class-E amplifier and lighting ballast using the amplifier

1. An amplifier comprising:

a power source;

a load network comprising a load and a resonance circuit;

an input branch having a first end electrically coupled to the power source and a second end electrically coupled to the load network, the input branch including at least one parallel-LC-circuit configured to provide an infinitely large impedance at harmonics of a determined order; and

an active switch having one terminal electrically coupled to the second end of the input branch.

2. The amplifier of claim 1 , wherein the power source is a direct current power source.

3. The amplifier of claim 1 , wherein the active switch comprises a terminal coupled to Ground.

4. The amplifier of claim 1 further comprising a shunt capacitor connected in parallel with the active switch.

5. The amplifier of claim 1 , wherein the load network further comprises an impedance matching circuit.

6. The amplifier of claim 1 , wherein a frequency of the resonance circuit is less than the switching frequency of the active switch.

7. The amplifier of claim 1 , wherein the active switch comprises a metal-oxide-silicon field-effect transistor.

8. The amplifier of claim 7 , wherein the metal-oxide-silicon field-effect transistor comprises a drain terminal electrically coupled to the second end of the input branch, and a source terminal connected to Ground.

9. The amplifier of claim 7 , wherein the metal-oxide-silicon field-effect transistor comprises a source terminal electrically coupled to the second end of the input branch, and a drain terminal connected to Ground.

10. The amplifier of claim 1 , wherein the parallel-LC-circuit provides an infinitely large impedance at a second harmonic frequency.

11. The amplifier of claim 1 , wherein the input branch includes at least two parallel-LC-circuits coupled in serial, the at least two parallel-LC-circuits respectively providing infinitely large impedances at second order harmonics.

12. The amplifier of claim 11 , wherein the at least two parallel-LC-circuits respectively provide infinitely large impedances at 2 nd and 4 th harmonics.

13. The amplifier of claim 1 , wherein the input branch further comprises a tunable inductor coupled in series with the parallel-LC-circuit.

14. A ballast circuit, comprising:

a direct current power supply;

an amplifier circuit comprising an input branch circuit electrically coupled to the direct current power supply to convert a direct current from the direct current power supply into an output alternating current signal, the input branch circuit including a harmonics reduction circuit with an infinitely large impedance to a determined order of harmonics;

an inductor coil to receive the output alternating current signal from the amplifier, and generate a magnetic field; and

a lighting device filled with ionizable gas coupled to the magnetic field to generate an arc discharge in response to the magnetic field.

15. The circuit according to claim 14 further comprising a starting circuit to provide a starting current for generating capacitive discharge in the lighting device before the lighting device enters into arc discharge.

16. The circuit according to claim 14 , wherein the input branch circuit of the amplifier comprises at least one parallel-LC-circuit configured to provide an infinitely large impedance at harmonics of a determined order.

17. The circuit according to claim 14 further comprising a control circuit to provide a timing and logic sequence to start the lighting device.

18. The circuit according to claim 14 further comprising a circuit and algorithm to control the warm up of the lighting device.

19. The circuit according to claim 14 further comprising a control circuit and algorithm to control the power of the lighting device.

20. The circuit according to claim 14 further comprising a control circuit to adjust the impedance matching network.