| 摘要 |
<p>An insulation resistance degradation detector (50) comprises a pulse generator (60) for applying a pulse signal (65) to a series circuit where a detecting resistor (70), a coupling capacitor (80), and an insulation resistor (Ri) are connected in series. A control circuit (110) detects a pulse divided voltage induced at a node (N1) through a bandpass filter (90) by means of a voltage detecting circuit (100) while the pulse signal (65) is applied to the series circuit so as to detect degradation of the insulation resistor (Ri). The control circuit (110) further detects a failure of the insulation resistance degradation detector itself when the voltage detected by the voltage detecting circuit (100) is kept above a predetermined voltage over a plurality of periods of the pulse signal (65). With this, an insulation resistance degradation detector having a failure self-diagnosis function is realized through a simple constitution.</p> |
