Differential fuse to protect voltage supply - has one earthed lead and uses two precision resistors in leads and differential amplifier

摘要

The differential fuse protects the supply leads of a voltage supply with one earthed lead and consumes little power. Two precision resistors (Rm) are connected between the supply poles (UB1) and the load (RL). A voltage divider (R1, R2) is connected across the load and a second voltage divider (R3, R4) across the two precision resistors and the load. - The tappings of the two dividers are connected to separate inputs of a differential amplifier whose output controls a switch (Ts1) in one supply lead. The amplifier output is also coupled via a diode and resistor (D, R5) back to one of its inputs.