Patent ID: 8299720

Claim:
An operating resonant load circuit, comprising: an input unit including a plurality of input terminals, to receive an Alternating Current (AC) voltage; a rectifier, to transform the AC voltage received by the input unit into a Direct Current (DC) bus voltage; and a controller, to divide the DC bus voltage based on a conducting status of the input terminals to output a corresponding DC reference voltage, wherein the controller comprises: a first voltage network, connected between a voltage bus and a reference ground of the circuit; a first control branch, comprising a second voltage network connected between a first input terminal of the input unit and the reference ground, and a first resistor and a first transistor connected in series between an intermediate node of the first voltage network and the reference ground, a base of the first transistor being connected to an intermediate node of the second voltage network; and a second control branch, comprising a third voltage network connected between a second input terminal of the input unit and the reference ground, and a second resistor and a second transistor connected in series between the intermediate node of the first voltage network and the reference ground, a base of the second transistor being connected to an intermediate node of the third voltage network.