Analyzing Charge-pump Inverter Circuit for Induction-coil Type Electrodeless Lamp

A charge-pump inverter circuit is useful for an induction-coil type electrodeless lamp system, and the input AC current harmonics can be reduced by using an additional diode and a small capacitance. However, the circuit operation is too complicated to understand because of the correlation between the load characteristics of the electrodeless lamp and the involved resonant circuits. This paper analyzes the circuit operation of this inverter circuit and derives some equations that are effective for improving the input AC current waveform near the zero-crossing points of the source voltage. Furthermore, two simplified equivalent models for the involved resonant circuits were assumed for an optimal design of the circuit parameters. The analytical waveforms were experimentally verified, and the input-current harmonics were reduced by the optimized circuit parameters so as to meet the IEC class C regulation.