Fuse failure display

摘要

Circuitry for fuse failure display for monitoring the trip status of a fuse is disclosed, wherein a light-emitting diode is provided in order to display the trip status of the fuse, which light-emitting diode is arranged in a current path parallel to the fuse. If the fuse is not tripped, the parallel current path has a high resistance in relation to the resistance across the fuse, such that the current across this current path is insufficient for operation of the light-emitting diode. If the fuse is tripped, this parallel current path has a low resistance in relation to the resistance across the fuse, such that the current across this current path is sufficient for operation of the light-emitting diode, wherein a current-limiting device for limiting the current across the light-emitting diode and a voltage-limiting device for limiting the voltage across the tripped fuse are also provided.

主权项

1. A circuit for fuse failure display for monitoring trip status of a fuse, the circuit comprising:
a light-emitting diode provided in order to display the trip status of the fuse; a current path parallel to the fuse in which the light emitting diode is arranged; wherein, if the fuse is not tripped, the current path has a high resistance in relation to a resistance across the fuse, such that current in the current path is insufficient for operation of the light-emitting diode, and wherein, if the fuse is tripped, the current path has a low resistance in relation to the resistance across the fuse, such that the current in the current path is sufficient for operation of the light-emitting diode; a current-limiting device for limiting the current through the light-emitting diode; and a voltage-limiting device for limiting the voltage across the tripped fuse; wherein, when the fuse is not tripped, a field-effect transistor and a resistor are provided in a series circuit in order to attain the high resistance of the current path and, when the fuse is tripped, the resistor is provided in order to arrange the current-limiting device in the parallel current path to provide a control voltage for the field-effect transistor in the current path with the light-emitting diode, wherein an off state of the field-effect transistor being dependent on said control voltage.