| 摘要 |
<p>The device comprises a dc voltage source (B), a dc/dc converter (1) operable to provide a higher voltage than that of the source (B), an inverter (2) to which the lamp (L) is connected and a control unit (ECU) which controls the converter (1) and/or the inverter (2) in such a way as to apply to the lamp (L) a higher power at striking and a lower power during subsequent operation of the lamp under normal conditions. Detector devices (R; 3, 4) provide signals to the unit (ECU) indicative of the impedance of the lamp (L). Non-volatile memory devices (M) associated with the unit (ECU) store data indicative of the values of the impedance (ZL) of the lamp upon variation of the time (toff) elapsed since it was extinguished. The unit (ECU) is arranged to acquire, at each striking, the impedance (ZL) presented by the lamp (L), to compare this impendence (ZL) with the values stored in the said memories (M), and to determine on the basis of this comparison the time (toff) elapsed since the lamp (L) was previously extinguished. <IMAGE></p> |
