Protection circuit and inverter

The embodiment of the invention relates to the technical field of electronic power. The invention provides a protection circuit, the structure of circuit is simple, the cost is low, and the sensitivity of the protection circuit is good. The protection circuit is applied to an inverter, the protection circuit comprises a current sampling circuit connected in series with a negative bus of an inverter direct-current link and also comprises a first amplifying circuit, a switching circuit, an isolating circuit, a second amplifying circuit and a control circuit which are sequentially connected withthe current sampling circuit, the first amplifying circuit is used for outputting a high-level signal when detecting a level signal higher than a first preset reference voltage; the second amplifyingcircuit is used for outputting a low-level signal when detecting a level signal higher than a second preset reference voltage; and the control circuit is used for turning off a switch device in the inverter when receiving the