Method and system for the recognition of insulation defects

US6140821A · kind A · utility

Assignee

• Temic Telefunken Microelectronik · DE

Inventors

• Gunter Fendt · Schrobenhausen, DE
• Hans Spies · Brackenheim, DE
• Peter Hora · Schrobenhausen, DE
• Guido Wetzel · Neubukow, DE

Key dates

• Filing date: Jun 26, 1998
• Grant date: Oct 31, 2000
• Expiry date: Jun 26, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/006
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention concerns a method for the recognition of insulation defects in a circuit adapted for connection to a low-ohmic current source or sink having off-load voltage U.sub.n0, Towards this end the circuit is initially subjected, in a separated state, to a diagnostic voltage from a current limited current source or sink whose off-load voltage U.sub.h0 corresponds to exceeds or, respectively, is less than the voltage U.sub.n0. A decision is made as to the presence or absence of an insulation defect based on the current and/or voltage dependence during application of the diagnostic voltage. Finally, in the event that a defect is present, an error message is issued and the low-ohmic current source or sink is not connected to the circuit for self-diagnosis. Otherwise, the low-ohmic current source is connected to the circuit, or the sink, in sequential fashion for self-diagnosis testing. In this fashion even hidden insulation defects are recognized. The invention also concerns a system for carrying out this method.