Patent ID: 6060844
Filing Date: 2000-05-09
Classification: H02M,H05B,Y02B

Abstract:
A ballast system for a fluorescent lamp, comprising:a rectifier converting an alternating input voltage to a rectified input voltage;a voltage converter converting said rectified input voltage to an output voltage higher than the rectified input voltage according to a voltage gain; andan inverter converting said high voltage to a high frequency output voltage;said voltage converter being coupled between said rectifier and inverter, and said voltage converter including:(a) a voltage generating circuit generating a compensation voltage to adjust said output voltage;(b) a switch circuit adjusting the compensation voltage;(c) a pulse generating circuit, coupled to said switch circuit and generating a sequence of pulses, wherein widths of the pulses controls switch-on and switch-off time of the switch circuit; and(d) a pulse width controlling circuit controlling the widths of the pulses generated by the pulse generating circuit.