Overload protection circuit for regulator setting element

摘要

The protection circuit uses a comparator (KO) allowing the setting value (UD) supplied to the setting element (F1) to be compared with a reference signal (Ur), with disconnection of the setting element upon reaching a defined energy loss. The comparator is preceded by an integrator (R1,C1) receiving the electrical setting value, its time constant corresp. to the thermic time constant of the setting element. Pref. FET's (F2,F3,F4) are used to provide a low ohmic bridge for the setting element outside the regulation mode, with simultaneous discharge of the capacitor (C1) of the RC element.