On-board supply system for use in motor vehicle, has field-effect-controlled power transistor applying supply voltage of system to load by logic circuit, where power transistor is in form of lower reverse voltage class

摘要

The system (1) has a field-effect-controlled power transistor (2) applying a supply voltage of the system to a load (4) by a logic circuit during controlling, where the power transistor has a drain source breakdown voltage with positive temperature coefficients. The power transistor is provided with a clamping unit for protecting from overvoltages, which appear in the system, where the power transistor is in the form of a lower reverse voltage class. A clamping voltage of the clamping unit is smaller or same as the maximum overvoltage to be estimated in the system. An independent claim is also included for a method for protecting an on-board supply system.