| 摘要 |
PURPOSE:To permit a proper lamp current to flow through each electric discharge lamp by controlling each lamp current for each electric discharge lamp by means of a switching element provided for each one. CONSTITUTION:Switching elements Q1 to Q4 are put into operation as switching elements for switching the polarity of lamp currents IDL1, IDL2 flowing through electric discharge lamps DL1, DL2 and therewith switching elements Q7, Q8 for high-frequency switching are added for use in current control of two electric discharge lamps DL1, DL2. The lamp currents IDL1, IDL2 flowing through the electric discharge lamps DL1, DL2, respectively, are here detected by current transformers CT1, CT2 and corresponding to the detecting amount a control circuit portion X2 controls the switching elements Q7, Q8. The lamp current can be thus controlled corresponding to each of the electric discharge lamps even if they have different properties. |
