Abstract: A detection circuit includes a detection power supply and a digital unit that are connected in series. A first end and a second end of the detection circuit are respectively connected to an input end and an output end of an anti-backflow circuit. The detection power supply may make an electric potential at the second end of the detection circuit higher than that at the first end of the detection circuit. When transmitting a detection current, the digital unit may output a first level signal indicating that the anti-backflow circuit fails. The detection current is a current transmitted when a loop is formed between the first end and the second end of the detection circuit.