Electrical vehicle circuitry

A transformer circuit 610 for an electric vehicle comprises: an input 530 for receiving electrical energy; a first output 521 for providing electrical energy to a first electrical bus of the vehicle at a first voltage (e.g. 800V); a second output 531 for providing electrical energy to a second electrical bus of the vehicle at a second voltage (e.g. 12V); and a multi-coil transformer 510 disposed between the input, the first output and the second output. The transformer may be omnidirectional and comprises: a primary winding 512 connected to the input; and first and second secondary windings 514, 516 connected to the first and second outputs respectively. The transformer can provide electrical energy to both outputs simultaneously. The first electrical bus provides power to, or receives power from, a traction battery of the vehicle. The second electrical bus provides power to one or more auxiliary electrical units of the vehicle. The input may be an AC input and ACDC converter 540, providing electrical energy to the primary winding via DC link capacitor bank 545 and primary side circuit 550 (e.g. inverter). A DC charging input 560 receives energy from a DC source and provides it to the primary winding via the primary side circuit.