Light source module, power supply unit for operating a light source module of this kind, and lighting system

A power supply unit for operating at least one light source module,

• the light source module comprising:
• at least one LED cascade with a plurality of LEDs connected in series;
• a supply line for coupling to a current source, wherein at the input side the LED cascade is coupled to the supply line;
• and
• a ground line for coupling to a reference potential;
• wherein
• the light source module further comprises:
• a communications line for coupling to a control device for the current to be provided by the current source;
• a thermal derating unit which is coupled between a first voltage source and the communications line and comprises a temperature-sensitive element,
• wherein the thermal derating unit is designed to apply a temperature dependent current component determined in dependence on the temperature-sensitive element, to the communications line;
• at least one current measurement resistor, which, forming a coupling point, is connected in series between the at least one LED cascade and the reference potential, wherein the conductance of the current measurement resistor is proportional to the current requirement of the LED cascade;
• and
• at least one coupling resistor, which is coupled between the coupling point and the communications line,
• wherein
• the power supply unit (PSU) comprises:
• an output with a first and a second output connector, wherein the first output connector is coupled to the supply line of the at least one light source module, wherein the second output connector is coupled to the ground line of the at least one light source module;
• a communications connector which is coupled to the communications line of the at least one light source module;
• an adjustable current source, which on the output side is coupled to the first output connector and to the second output connector in order to provide an output current, wherein on the input side the current source has a control connector;
• a regulating switch which on the input side is coupled to the communications connector and on the output side to the control connector of the current source,
• wherein the regulating switch comprises a control circuit which is designed, as a function of the voltage signal on the communications connector, to determine a nominal value of the current to be provided by the current source, and through the voltage level on the communications line to regulate the actual value of the current provided by the current source in dependence on said nominal value, wherein the control circuit has a negative feedback designed in such a way that the control circuit does not influence the direct voltage value of the signal on the communications line.

A lighting system (BEL) comprising a power supply unit and at least one light source module which is connected to the power supply unit,

• the power supply unit being configured to operate the at least one light source module,
• the light source module comprising:
• at least one LED cascade with a plurality of LEDs connected in series;
• a supply line for coupling to a current source, wherein at the input side the LED cascade is coupled to the supply line;
• and
• a ground line for coupling to a reference potential;
• wherein
• the light source module further comprises:
• a communications line for coupling to a control device for the current to be provided by the current source;
• a thermal derating unit which is coupled between a first voltage source and the communications line and comprises a temperature-sensitive element, wherein the thermal derating unit is designed to apply a temperature dependent current component determined in dependence on the temperature-sensitive element, to the communications line;
• at least one current measurement resistor, which, forming a coupling point, is connected in series between the at least one LED cascade and the reference potential, wherein the conductance of the current measurement resistor is proportional to the current requirement of the LED cascade;
• and
• at least one coupling resistor, which is coupled between the coupling point and the communications line,
• wherein
• the power supply unit comprises:
• an output with a first and a second output connector, wherein the first output connector is coupled to the supply line of the at least one light source module, wherein the second output connector is coupled to the ground line of the at least one light source module;
• a communications connector which is coupled to the communications line of the at least one light source module;
• an adjustable current source, which on the output side is coupled to the first output connector and to the second output connector in order to provide an output current, wherein on the input side the current source has a control connector;
• a regulating switch which on the input side is coupled to the communications connector and on the output side to the control connector of the current source,
• wherein the regulating switch comprises a control circuit which is designed, as a function of the voltage signal on the communications connector, to determine a nominal value of the current to be provided by the current source, and through the voltage level on the communications line to regulate the actual value of the current provided by the current source-in dependence on said nominal value, wherein the control circuit has a negative feedback designed in such a way that the control circuit does not influence the direct voltage value of the signal on the communications line.