| 摘要 |
PURPOSE:To reduce heat generated from a switching element and a stress. CONSTITUTION:A discharge preventive circuit 5 for preventing flow of a discharge current from a capacitor C2 is provided in a switching element Q2. When the discharge current of the capacitor C2 flows in a loop of a current transformer CT, a discharge lamp L, etc., a current flows to a diode D1. A switching element Q4 is closed by an ON voltage of a diode D1, a base current of the element Q2 is extracted, and supplied to the capacitor C2. When the discharge of the capacitor C2 is finished, no current flows to the diode D1, and hence an ON voltage is not generated across the diode D1. Thus, the element Q4 is opened, a base current flows to the element Q2, and the element Q2 is closed. |
