Protective device and fieldbus module comprising a protective device

A fieldbus module comprising an interface unit for linking to a fieldbus, comprising:

• an input for feeding with a supply energy, comprising an output for forwarding the supply energy to a further fieldbus module, and comprising a protective device,
• wherein the protective device comprises a switch arrangement connected between the input and the output in order to limit the current of the supply energy flowing between the input and the output,
• wherein the switch arrangement comprises a first power switch, a second power switch and a drive unit connected to the first and second power switches for controlling the power switches,
• wherein the first and second power switches are electrically connected in parallel with one another between the input and the output, as a result of which a first part of the current flowing between the input and the output may flow as a first forward current through the first power switch and a second part of the current flowing between the input and the output may flow as a second forward current through the second power switch,
• wherein the first power switch is configured to conduct the first forward current in a conducting state of the first power switch and to limit the first forward current in a current-limiting state of the first power switch,
• wherein the second power switch is configured to conduct the second forward current in a conducting state of the second power switch and to interrupt the second forward current in an interrupting state of the second power switch,
• wherein the second power switch in the conducting state of the second power switch comprises a lower on resistance than the first power switch in the conducting state of the first power switch, and
• wherein the switch arrangement is configured, for the purpose of limiting the current flowing between the input and the output, to interrupt the second forward current by the interrupting state of the second power switch and to limit the first forward current by the current-limiting state of the first power switch.

The protective device comprises a first power switch, a second power switch and a drive unit,

• wherein the first power switch comprises a first control connection and the second power switch comprises a second control connection,
• wherein a first forward current is controllable by a control signal applicable to the first control connection of the first power switch,
• wherein a second forward current is controllable by a control signal applicable to the second control connection of the second power switch,
• wherein the first and second control connection, for the purpose of having a common control signal applied to them, are connected to a control output of the drive unit,
• wherein the first power switch is configured to limit the first forward current in the current-limiting state of the first power switch if a common limiting signal is present as the common control signal at the first control connection of the first power switch, and
• wherein the second power switch is configured to interrupt the second forward current in the interrupting state of the second power switch if the common limiting signal is present at the second control connection of the second power switch.