A safety trip device for protection of a load in a low voltage circuit has a protection circuit comprising a MOSFET transistor Q1, a latch off control 2, a resistor R1, and a voltage reference Vref. These components are arranged such that during normal operation the voltage drop across MOSFET Q1 is replicated across resistor R1 and compared with voltage reference Vref such that when the voltage across R1 is less than Vref, Q1 conducts and when the voltage across R1 is greater than Vref, Q1 is latched off. The device may further comprises a start-up protection circuit that allows an initial overcurrent for a limited time period when the protection circuit is started up. This may be achieved by additionally providing the protection circuit with a capacitor C1, resistors R2 and R3, and a MOSFET transistor Q2 and suitably arranging them within the protection circuit.
展开▼
