Patent ID: 6380695
Filing Date: 2002-04-30
Classification: H02M,H05B

Abstract:
A driving device for a fluorescent tube, comprising:a high frequency oscillator having an input terminal connected to a power source, and an output terminal for outputting a high frequency AC signal; a pulse width modulator (PWM) having an input terminal connected to the output terminal of the high frequency oscillator, and an output terminal for outputting a PWM harmonic frequency signal; a first power switch connected to the output terminal of the pulse width modulator for being turned off during a positive half-cycle of the PWM harmonic frequency signal and being turned on during a negative half-cycle of the PWM harmonic frequency signal; a second power switch connected to the output terminal of the pulse width modulator for being turned on during the positive half-cycle of the PWM harmonic frequency signal and being turned off during the negative half-cycle of the PWM harmonic frequency signal; and a piezoelectric transformer having a primary winding and a secondary winding, the primary winding having two input terminals connected to the first power switch and the second power switch, respectively, and a center terminal connected to the output terminal of the pulse width modulator.