Patent ID: 8174203

Claim:
A lamp driving circuit, comprising: a first printed circuit board; and a second printed circuit board, wherein the first printed circuit board includes: a switching unit for switching an input power source; a control unit for controlling the switching unit; an inverter transformer connected to the switching unit; a voltage conversion unit connected to the inverter transformer and the control unit for converting a feedback reference current for controlling an output current applied from the inverter transformer into a reference voltage to apply the reference voltage to the control unit; and a first feedback terminal connected to the voltage conversion unit, and the second printed circuit board includes: a plurality of balance coils connected to a plurality of lamps so that the same output currents are applied to the lamps; a second feedback terminal connected to the first feedback terminal; and a current conversion unit connected to the second feedback terminal, wherein the current conversion unit includes a plurality of resistors connected in parallel, and the reference voltage applied to the control unit is changeable by changing a resistance of the current conversion unit.