Patent ID: 6072285
Filing Date: 2000-06-06
Classification: H05B,Y10S

Abstract:
A soft starter device for lamps comprising:a rectifying( circuit electrically connected to ain AC power source for converting an AC voltage into a DC voltage which servers as a triggering signal;a high frequency voltage generating circuit electrically connected to the rectifying circuit and having two transistors and an output capacitor for generating a high frequency voltage,a high frequency output transformer electrically connected to the high frequency voltage generating circuit and having a primary coil and a secondary coil magnetically coupled to each other, wherein one terminal of the primary coil is electrically connected to one terminal of the output capacitor, and the other terminal of the primary coil and one terminal of the secondary coil are electrically connected to both ends of a lamp tube;a first capacitor electrically connected to both ends of the lamp tube for supplying a momently high voltage to start the lamp tube by generating a resonance together with the high frequency output transformer;a control circuit electrically connected to the other terminal of the secondary coil and having a charging circuit and a switch, wherein the charging circuit provides a charging current to turn the switch so as to ground the secondary coil which is electrically connected to the switch at the initial time of current supply by the AC power supply, at this time, the primary coil cannot function normally, such that a current flows from the output capacitor to the lamp tube to preheat the filaments thereof, and the switch is turned off after a charging time to allow the secondary coil to function normally, thereby generating a resonance together with the first capacitor to smoothly start the lamp tube.