Protective circuit with current regulating digital output module

A combination comprising:

• a digital output module having at least one output channel connected to a protective circuit;
• wherein the protective circuit comprises:
• a first sampling unit configured to sample a first voltage relevant to an output current sampling from a first voltage source to a load;
• a first comparing unit configured to compare the sampled first voltage with a first reference voltage;
• a control unit configured to generate a current regulating signal and a voltage source control signal based on a result from the first comparing unit, the control unit comprising a transistor having a base junction;
• a current regulating unit configured to selectively interrupt the output current from the first voltage source to the load based on the current regulating signal,
• a voltage source control terminal configured to be coupled to the first voltage source and control the voltage source control signal output from the control unit to the current regulating unit;
• and
• wherein the voltage source control terminal is configured to be coupled to the base junction of the transistor and a second voltage source by way of a diode, and coupled to a third voltage source, and to selectively interrupt the current regulating signal based on a signal from the digital output module.

A protective circuit to be used in a digital output module, the digital output module comprising a first voltage source and at least an output terminal,

• wherein the protective circuit comprising:
• a first sampling unit configured to sample a first voltage relevant to a output current from the first voltage source;
• a first comparing unit configured to compare the sampled first voltage with a first reference voltage;
• a control unit configured to generate a current regulating signal based on a result from the first comparing unit;
• and
• a current regulating unit configured to regulate the output current from the first voltage source based on the current regulating signal,
• wherein the current regulating unit comprises a first transistor having a base junction, an emitter junction and a collector junction, the first transistor is configured to be conductive under a low level on the base junction which is lower than a cut-off voltage
• wherein the control unit comprises a second transistor having a base junction connected to a second voltage source via a first resistor, an emitter junction and a collector junction, wherein the second transistor is configured to be conductive under a high level on the base junction which is higher than a cut-off voltage;
• wherein the collector junction of the second transistor is connected to the base junction of the first transistor via a first resistor unit, the base junction of the second transistor is connected to an output of the first comparing unit, and the emitter junction of the second transistor is connected to a grounding plane;
• and
• wherein the control unit comprises a first capacitor connected between the base junction of the first transistor and the first voltage source.