Power supply circuit, power supply system and vehicle

The embodiment of the invention provides a power supply circuit, a power supply system and a vehicle, the power supply circuit comprises a DC/DC power supply module and a peripheral module, and the peripheral module comprises a transformer, a primary side circuit and a secondary side circuit; a first input end of the primary side circuit is connected with an output end of the DC/DC power supply module, a first output end of the primary side circuit is connected with a first end of a primary side winding of the transformer, a second input end of the primary side circuit is grounded, and a second output end of the primary side circuit is connected with a second end of the primary side winding of the transformer; a first input end of the secondary circuit is connected with a first end of a secondary winding of the transformer, a second input end of the secondary circuit is connected with a second end of the secondary winding of the transformer, and a second output end of the secondary circuit is grounded; the second output end of the primary side circuit outputs positive voltage, and the first output end of the secondary side circuit outputs negative voltage. According to the power supply circuit, the reliability of the positive voltage and the negative voltage provided by the power supply circuit can be improved.