SURGE ABSORPTION CIRCUIT, POWER SUPPLY DEVICE, DISCHARGE LAMP LIGHTING DEVICE AND LIGHTING SYSTEM

摘要

PURPOSE:To provide a discharge lamp lighting device having the capability of preventing a switching element from being damaged, while effectively utilizing surge energy. CONSTITUTION:The AC voltage of a commercial AC power supply E is full- wave rectified via a full-wave rectifier 21, and a field effect transistor Q1 is caused to oscillate via a bypass capacitor C1 according to a control means 23, thereby actuating a chopper circuit 24. An inverter circuit 25 oscillates at a high frequency for converting the voltage to high frequency AC current, thereby lighting a discharge lamp FL. When input voltage rises due to surge, the control means 23 turns off the field effect transistor Q1. The surge energy charges a capacitor C2 from an inductor L1 via a diode D1, and this capacitor C2 smooths the charged voltage for outputting to the inverter circuit 25.