An exemplary inverter circuit (2) includes a full-bridge circuit (21) for converting a DC voltage into an AC low voltage, main inverse transformers (22) for converting the AC low voltage into an AC high voltage, and a feedback circuit (25). The feedback circuit includes a secondary inverse transformer (250) for converting the AC low voltage into an AC high voltage, a sampling unit (254) for sampling the AC high voltage and outputting a sampling voltage, and an integral circuit unit (205) for integrating the sampling voltage and outputting an integrated sampling voltage to the full-bridge circuit. When the AC low voltage outputted by the full-bridge circuit fluctuates, the feedback circuit sends a feedback voltage to the full-bridge circuit, and the full-bridge circuit stabilizes the AC low voltage according to the feedback voltage. The feedback voltage is in direct proportion to the fluctuation of the AC low voltage.