METHOD AND DEVICE FOR DRIVING A GAS DISCHARGE LAMP

摘要

A method is described for reducing infrared emission from a gas discharge lamp (2) driven in a dimmed condition, the lamp having a nominal rating corresponding to a nominal lamp current magnitude (Im) and a nominal light output. The method comprises the step of driving the lamp at a dimmed light output by alternatively operating the lamp in a high power state (H) and in a low power state (L). During the high power state (H), the lamp is supplied with alternating lamp current having the nominal lamp current magnitude (Im) and having a predetermined commutation frequency. During the low power state (L), the lamp is supplied with reduced alternating lamp current having the same predetermined commutation frequency and havinga reduced current magnitude (Ix) less than the nominal lamp current magnitude (Im) but higher than zero.