Supply of air to an air-conditioning circuit of an aircraft cabin

An aircraft turboprop engine has at least one low-pressure body and one high-pressure body. The low-pressure body drives a thrust propeller using a gearbox. The turboprop engine further includes a means for supplying air to an air-conditioning circuit of an aircraft cabin. The supply means includes a load compressor and a rotor that is coupled to the low-pressure body by the gearbox. The supply means further includes a means for controlling the rotation speed of the rotor of the compressor, which means comprise an electric motor, and a mechanical differential for coupling a first output shaft of said electric motor to a second output shaft of said gearbox and to said compressor rotor, such that the rotation speed of said rotor depends on the respective rotation speeds of said first and second output shafts.