Flyback converter having two or more independent output stages

A method for supplying power to an electric motor vehicle control device with a power supply unit comprising a transformer with a primary coil that is actuatable by way of a switchable primary switch and with a secondary coil, wherein the primary coil and the secondary coil are disposed on a common magnetic core, wherein the secondary coil provides outputs with controllable output voltages, wherein the secondary coil is assigned a switchable secondary switch for each of the outputs, the power supply unit comprising a signal processing and calculation unit, the method comprising:

• actuating the primary switch and the secondary switches by way of pulse generators controlled by the signal processing and calculation unit;
• outputting a clocked control signal by way of a primary pulse generator to the primary switch so that the primary switch is switched on for a first time, as a result of which a current flows through the primary coil and generates a magnetic field in a magnetic core and the primary switch then goes into an off state for a second time;
• and
• sequentially switching on the outputs by way of the secondary switches during the off state of the primary switch, wherein a switch-on process in each case lasts until a setpoint value of the respective output voltage is reached or a predetermined time is exceeded.