Electronic unit and method for detecting a polarity inversion of the onboard power supply voltage in motor vehicles

摘要

An electronic unit in a motor vehicle has a connection for the negative onboard power supply voltage and a connection for the positive onboard power supply voltage, as well as an internal electric supply unit that can be used independently of the polarity of the onboard power supply voltage and independently of the onboard power supply voltage. The unit includes a function block which compares the actual voltage at the connection for the negative onboard power supply voltage with the actual voltage at the connection for the positive onboard power supply voltage. A polarity inversion of the onboard power supply voltage is detected (and a storage of the polarity inversion detection data is caused) if the actual voltage at the connection for the negative onboard power supply voltage is higher than the actual voltage at the connection for the positive power supply voltage, or if the respective actual voltages exceed preset reference values.