Patent ID: 7593241

Claim:
A hybrid power supply system for driving a discharge lamp, the hybrid power supply system comprising: a rectifier/filter having an input terminal connected to an external AC voltage, the rectifier/filter converting the external AC voltage to a DC voltage; a piezoelectric inverter connected to the rectifier/filter, the piezoelectric inverter stepping up and converting the DC voltage to an AC voltage for driving the discharge lamp; and a ferrite converter connected to the rectifier/filter, the ferrite converter stepping down the DC voltage to a rated DC voltage for driving discharge lamp circuits other than the discharge lamp, the piezoelectric inverter including: two first switching circuits having respective input terminals and a common output terminal; a driver circuit electrically coupled to respective control input terminals of the first switching circuits, the driver circuit driving the first switching circuits; at least one piezoelectric step-up transformer having a primary side electrically coupled to the common output terminal of the first switching circuits and a secondary side electrically coupled to the discharge lamp; a sampling circuit electrically coupled to the discharge lamp, the sampling circuit detecting a current value of the discharge lamp and outputting a feedback signal; a comparator circuit electrically coupled to the sampling circuit and a frequency control circuit, the comparator circuit comparing the feedback signal with a predetermined reference signal; and the frequency control circuit electrically coupled to the comparator circuit and the driver circuit, the frequency control circuit controlling a switching frequency for the switching circuits according to an output signal of the comparator circuit, the ferrite converter including a ferrite step-down transformer and a rectifier circuit, the ferrite step-down transformer having a primary side electrically coupled to the output terminal of the switching circuits and a secondary side electrically coupled to the rectifier circuit, the rectifier circuit electrically coupled to the secondary side of the ferrite step-down transformer.