| 摘要 |
PURPOSE:To reduce the cost of a switching regulator which is inserted into the primary side circuit of a DC converter by performing the drive of the regulator at the power source energizing time by the primary side circuit itself, thereby simplifying the structure. CONSTITUTION:When a power source switch S is closed, the condenser C1 at the output side of a rectifier 4 is charged. When the charging voltage becomes a value or higher, a switching transistor Q1 is conducted. As a result, a DC converter 2 is energized, and an AC is generated at the output coils N2-N7 of an inverter transformer T1. The AC generated at the coil N6 is converted by a diode D2 and a condenser C3 into a DC. This DC holds the transistor Q1 in conductive state. Then, the duty of the transistor Q1 is controlled so that the current of a fluorescent lamp is always equalized to the set value. |
