US 12,066,479 B2
Insulation resistance detection circuit and method of detecting insulation resistance
Li-Ching Yang, Taoyuan (TW); Wen-Lung Huang, Taoyuan (TW); and Sheng-Hua Li, Taoyuan (TW)
Assigned to DELTA ELECTRONICS, INC., Taoyuan (TW)
Filed by DELTA ELECTRONICS, INC., Taoyuan (TW)
Filed on Aug. 22, 2022, as Appl. No. 17/892,512.
Claims priority of application No. 111110507 (TW), filed on Mar. 22, 2022.
Prior Publication US 2023/0305052 A1, Sep. 28, 2023
Int. Cl. H01H 31/12 (2006.01); G01R 31/14 (2006.01)
CPC G01R 31/14 (2013.01) 12 Claims
OG exemplary drawing
 
1. 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 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 detection unit is configured to set a first estimated resistance of the positive insulation resistance and a second estimated resistance of the negative insulation resistance, and acquire a first voltage based on turning on the switch and acquire a second voltage based on turning off the switch,
wherein the detection unit is configured to calculate a third voltage and a fourth voltage according to the first estimated resistance and the second estimated resistance so as to detect the positive insulation resistance and the negative insulation resistance when the third voltage is equal to the first voltage and the fourth voltage is equal to the second voltage.