Insulation detection circuit and method, and battery management system

An insulation detection circuit, comprising a first isolation module, a voltage division module, a signal generation module, a first sampling point, a second sampling point and a processor, wherein:

• a first end of the first isolation module is connected to a positive electrode of a power battery under detection, and a second end of the first isolation module is connected to the second sampling point;
• the signal generation module is connected to the first sampling point and configured to inject an AC signal of a predetermined frequency into the power battery under detection and provide the first sampling point with a first sampled signal of the predetermined frequency;
• a first end of the voltage division module is connected to the first sampling point, a second end of the voltage division module is connected to the second sampling point, and the voltage division module is configured to provide the second sampling point with a second sampled signal;
• and
• the processor is configured to calculate an insulation resistance of the power battery under detection according to the first sampled signal and the second sampled signal.