A main semiconductor device for controlling an air conditioner provided in a vehicle and selectively connected to an air-conditioning panel semiconductor that controls an air-conditioning panel may include: an analog circuit unit and a digital circuit unit, an input module receiving sensor information for controlling the air conditioner, a motor driving module driving one or more motors provided in the air conditioner, a voltage regulator module regulating a voltage supplied to each module of the main semiconductor device, and a control module controlling the motor driving module based on the sensor information received by the input module, and constantly supplying a voltage to each module of the main semiconductor device by controlling the voltage regulator module.