Patent ID: 8878543
Filing Date: 2014-11-04
Classification: B60L,G01R

Abstract:
1. A vehicular insulation resistance detection apparatus that detects an insulation resistance between a low-voltage circuit and a high-voltage circuit, comprising: a cyclic signal generating unit that generates a cyclic signal which has a preset frequency; a first resistor that has one end which is connected to the cyclic signal generating unit, the cyclic signal being applied to the one end; a first capacitor that has one end which is connected to an other end of the first resistor and an other end which is connected to the high-voltage circuit; a second capacitor that has one end which is connected to the other end of the first resistor; a second resistor that has one end which is connected to an other end of the second capacitor and an other end which is connected to a low-voltage ground that is a circuit ground of the low-voltage circuit; a series circuit that includes a diode and a third resistor connected in series, and is connected in parallel with the second capacitor, the diode having a forward direction coincident with a direction from the other end of the second capacitor to the one end of the second capacitor; a voltage detection unit that detects a voltage between the low-voltage ground and the other end of the second capacitor as a detection signal; and an insulation resistance detection unit that detects a resistance value of the insulation resistance based on an amplitude of the detection signal.