Power device detection circuit, power device detection method and power device

The invention discloses a power device detection circuit, a power device detection method and a power device, applies to the power supply technical field and solves the technical problems that it is difficult to debug a PD detection scheme and the PD detection scheme can only be applied to a power supply device about 40-55 V in the prior art. The power device detection circuit is applied to a PoE device. The power device detection circuit comprises a PD polling circuit, a PD judgment circuit, a first Ethernet port, a power output switch and a power circuit change-over switch. The technical scheme can support the use of the power supply device lower than 40 V, and flexible application is realized; and the adopted feedback judgment circuit is easy to debug, and the scheme is easier to realize.