ELECTROLESS DISCHARGE LAMP LIGHTING DEVICE AND LIGHTING SYSTEM USING THE DEVICE

摘要

PURPOSE: To enable stable action to be achieved and to start a lamp well even if a pulsating current is used as main power supply by constituting a low-cost control circuit which does not use an expensive PLL circuit nor a DC stabilizing power circuit. CONSTITUTION: A pulsating (direct) current produced from an alternating current from an AC power supply 1 by means of a rectifying circuit 2 is converted into a high-frequency alternating current by a DC/high-frequency inverter circuit and supplied to an exciting coil 7 via a matching circuit 6 so that a discharge map 8 is started. Voltages which a detecting circuit 13 detects at both ends of the exciting coil 7 are supplied to a peak detection holding circuit to hold their peak values. The peak values are compared with a reference value by an error amplifier 11, and a VCO 12 varies an oscillating frequency according to the result of the comparison, and frequency control is performed by the DC/high-frequency converter circuit 4. Thus the frequency control can be performed in such a way that the peak values are held constant.