| 摘要 |
A miniaturized electronic control circuit and method for igniting and controlling the operation of an arc lamp in a hand held search light is disclosed. A modulator provides output pulses at a variable duty cycle to a switched regulator which provides an output voltage to a first electrode of the arc lamp. The magnitude of the output voltage of the regulator varies in accordance with the duty cycle of the output pulses from the modulator. A lamp igniter is coupled between a first control input to the modulator and a second electrode of the arc lamp. The lamp igniter, in response to a first magnitude in the output voltage from the switched regulator, effects the generation of a high voltage pulse to ignite the arc lamp. Substantially at the time of ignition, the lamp igniter provides a signal proportional to lamp current to the control input to the modulator to alter the duty cycle of the output pulses therefrom to change the output voltage from the switched regulator from the first magnitude to a second magnitude to sustain operation of the arc lamp by controlling the current flowing through the arc lamp. The lamp igniter has an inductance serving to minimize in rush current to the lamp during lamp ignition. The electronic control circuit further includes an intensity control switch for providing a light intensity control signal to a second control input to the modulator to effect changes in the duty cycle of the output pulses provided to the switched regulator to selectively change the magnitude of the output voltage from the switched regulator to thus switch the intensity of the light emitted by the arc lamp by changing the magnitude of the current flowing through the arc lamp.
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