Insulation resistance detection circuit

An insulation resistance detection circuit, coupled to a positive end and a negative end of a DC power source, and configured to detect a positive insulation resistance between the positive end and a ground point, and a negative insulation resistance between the negative end and the ground point, the insulation resistance detection circuit comprising:

• a first resistance, a second resistance, a third resistance, and a fourth resistance coupled in series, and a first node between the second resistance and the third resistance coupled to the ground point,
• a first circuit bypass capacitance and a second circuit bypass capacitance, the first circuit bypass capacitance coupled in parallel to the first resistance and the second resistance in series, and the second circuit bypass capacitance coupled in parallel to the third resistance and the fourth resistance in series,
• a switch comprising a first end and a second end, the first end coupled to a second node between the first resistance and the second resistance, and the second end coupled to a third node between the third resistance and the fourth resistance, and
• a detection unit coupled to any two of the positive end, the negative end, the first node, the second node, and the third node,
• wherein the first resistance and the second resistance are configured for the first circuit bypass capacitance discharging to the ground point, the third resistance and the fourth resistance are configured for the second circuit bypass capacitance discharging to the ground point.