Oscillator generators and methods of using them
Certain embodiments described herein are directed to generators that can be used to sustain a plasma. In some embodiments, the generator comprises an oscillation circuit configured to electrically couple to an induction device and provide power to the induction device in an oscillation mode to sustain the inductively coupled plasma in a torch body, the circuit configured to provide harmonic emission control during sustaining of the inductively coupled plasma in the torch body in the oscillation mode of the generator.
1. A system comprising:
an induction device; and
a generator electrically coupled to the induction device and configured to sustain an inductively coupled plasma in a torch body, the generator comprising a processor and an oscillation circuit electrically coupled to the processor, the oscillation circuit configured to provide power to the induction device in an oscillation mode to sustain the inductively coupled plasma in the torch body, wherein the circuit is further configured to provide harmonic emission control during sustaining of the inductively coupled plasma in the torch body in the oscillation mode of the generator.
2. The system of claim 1 , in which the circuit comprises a first transistor and a second transistor each electrically coupled to the induction device.
3. The system of claim 2 , in which the circuit further comprises a first driver electrically coupled to the first transistor and electrically coupled to the induction device.
4. The system of claim 3 , in which the first driver is electrically coupled to the induction device through a first low pass filter.
5. The system of claim 4 , in which the circuit further comprises a second driver electrically coupled to the second transistor and electrically coupled to the induction device.
6. The system of claim 5 , in which the second driver is electrically coupled to the induction device through a second low pass filter.
7. The system of claim 6 , in which each of the first low pass filter and the second low pass filter is configured to filter a feedback signal provided to the first power transistor and the second power transistor.
8. The system of claim 7 , in which each of the first low pass filter and the second low pass filter comprise a high order ceramic low-pass filter.
9. The system of claim 8 , in which the high order ceramic low pass filter is configured to provide at least a 20 dB cut off at 200 MHz or higher frequencies.
10. The system of claim 1 , in which the circuit is configured to provide impedance matching within about three RF cycles.
11. The system of claim 1 , further comprising a detector electrically coupled to the processor and configured to determine when the plasma is ignited.
12. The system of claim 11 , in which the processor is configured to disable the oscillation circuit if the plasma is extinguished.
13. The system of claim 11 , further comprising a signal converter between the processor and the detector.
14. The system of claim 1 , in which the induction device comprises an induction coil or a plate electrode.
15. The system of claim 2 , in which the oscillation circuit is configured to divide power evenly to the first transistor and the second transistor.
16. The system of claim 15 , in which the oscillation circuit is configured to cross couple feedback signals from the induction device to the first transistor and the second transistor to divide the power evenly.
17. The system of claim 16 , in which the oscillation circuit comprises a first feedback resistor electrically coupled to the first transistor.
18. The system of claim 17 , in which the oscillation circuit comprises a second feedback resistor electrically coupled to the second transistor.
19. The system of claim 18 , in which the oscillation circuit comprises a first DC block capacitor electrically coupled to the first transistor.
20. The system of claim 19 , in which the oscillation circuit comprises a second DC block capacitor electrically coupled to the second transistor.