| 摘要 |
A self-tuned system includes an oscillator (30) and an oscillator-driven load which uses the oscillator-driven load as a frequency determining element of the resonant system. In one illustration, the oscillator-driven load is a lamp head circuit for an electrodeless lamp. The lamp head circuit of the electrodeless lamp comprises an excitation coil (40) proximate an envelope or bulb (42) enclosing a fill, the fill forming a plasma discharge when ignited. Various oscillator configurations can be used with the load, including modified Hartley (30A), modified Colpitts (Clapp) (30B), and modified Armstrong configurations (30C). Various embodiments of clamping circuits (100) can also be utilized to limit a feedback signal applied by the feedback system to a region tolerated by the amplifier. Of particular interest to the present invention are self-tuned systems which operate at high frequency and high power. Example implementations of high frequency and high power electrodeless lamps are provided, as well as various inventive techniques for, e.g., providing sufficient gain and for enhancing ignition/self-starting (e.g., reducing start time) of high frequency, high power self-tuned systems. Techniques and arrangements for ensuring sufficient gain for the self-tuned systems of the invention include choice of oscillator configuration, multi-stage amplification (when required), and feedback system configuration. Self-ignition of the load is achieved in numerous ways, such as (for example) using a special starting oscillator; using a low pressure rare gas fill for the lamp bulb; and increasing current in the excitation coil (e.g., by selectively positioning a juncture of a tap (60) to the excitation coil). |
