초록 ▼

To control low-pressure fluorescent lamps, there is provided a device comprising a first change-over switch circuit and a second change-over switch circuit, respectively including a first power transistor and a second power transistor. The first change-over switch circuit first of all measures the p

To control low-pressure fluorescent lamps, there is provided a device comprising a first change-over switch circuit and a second change-over switch circuit, respectively including a first power transistor and a second power transistor. The first change-over switch circuit first of all measures the period of time when the second power transistor is on. Then, secondly, it turns the first power transistor on for a period equal to the period measured.

대표청구항 ▼

[ What is claimed is:] [1.] A single switch electronic ballast which powers a lamp, the ballast comprising:a switch configured as a Class E, inverter;a feedback path connected to supply the switch with a regenerative feedback current, the feedback path including a first winding of a transformer, a f

[ What is claimed is:] [1.] A single switch electronic ballast which powers a lamp, the ballast comprising:a switch configured as a Class E, inverter;a feedback path connected to supply the switch with a regenerative feedback current, the feedback path including a first winding of a transformer, a feedback inductor, and a charging capacitor;a starting resistor network connected to a high side bus and a low side bus in order to receive a rectified dc voltage;a current source inductor connected to receive the dc voltage and to generate a dc current for powering the ballast;zener diodes connected between the switch and the transformer, the current source inductor;a blocking capacitor connected across the switch and to a second winding of the lamp, wherein upon startup the charging capacitor charges up through starting resistor network until the charging capacitor reaches a threshold value which biases switch on, and wherein upon turning on, switch oscillates until reaching a switching mode.[ What is claimed is:] [1.] A control device for a low-pressure fluorescent lamp comprising a first change-over switch circuit and a second change-over switch circuit series-connected between a high voltage and the ground, a first change-over switch circuit comprising a first power transistor, the second change-over switch circuit comprising a second power transistor, an inductor being series-connected with the low-pressure fluorescent lamp and with a capacitor between the midpoint of the two change-over switch circuits and the ground,wherein the first change-over switch circuit comprises:a circuit for measuring the period during which the second power transistor is on to measure a first period; anda switching-on circuit to turn the first power transistor on during a second period that is consecutive and equal to the first period.