Circuit unit

1. A circuit unit ( 8 ) for a radiation-producing semiconductor unit ( 2 ), wherein during operation a forward voltage U f is applied to the radiation-producing semiconductor unit ( 2 ) and the radiation-producing semiconductor unit ( 2 ) has a forward current I f flowing through it, wherein

the circuit unit ( 8 ) regulates the forward current I f such that an actual value V act , which is dependent on the forward current I f and the forward voltage U f , assumes a prescribed setpoint value V set

wherein the forward current I f is a clocked current; the circuit unit ( 8 ) has an actuation unit ( 4 ) and an evaluation unit ( 3 ); and wherein the evaluation unit ( 3 ) has an averaging element ( 2 ) for the purpose of ascertaining an average forward current I f .

2. The circuit unit ( 8 ) as claimed in claim 1 , wherein the evaluation unit ( 3 ) comprises a nonreactive resistor ( 9 ).

3. The circuit unit ( 8 ) as claimed in claim 2 , wherein the forward current I f is ascertained using a voltage drop across the nonreactive resistor ( 9 ).

4. The circuit unit ( 8 ) as claimed in claim 2 , wherein the nonreactive resistor ( 9 ) is connected in series with the radiation-producing semiconductor unit ( 2 ).

5. The circuit unit ( 8 ) as claimed in claim 1 , wherein

the evaluation unit ( 3 ) comprises a mathematical circuit ( 10 ).

6. The circuit unit ( 8 ) as claimed in claim 1 , wherein

the actual value V act is a function f of the forward voltage U f and the forward current I f , wherein one of the following correlations applies: V act =f(U f *I f ); V act =f(U f /I f ); V act =f(U f +I f ); V act =f(U f −I f ).

7. The circuit unit ( 8 ) as claimed in claim 5 or 6 , wherein the actual value V act is ascertained using the mathematical circuit ( 10 ).

8. The circuit unit ( 8 ) as claimed in claim 1 ,

wherein

the forward current I f is a direct current.

9. The circuit unit ( 8 ) as claimed in claim 1 , wherein

the evaluation unit ( 3 ) has at least one first element ( 11 ) for determining the difference between V act and V set .

10. The circuit unit ( 8 ) as claimed in claim 9 , wherein the first element ( 11 ) is a subtractor which is used as a regulator.

11. The circuit unit ( 8 ) as claimed in claim 1 , wherein the actuation unit ( 4 ) is electrically conductively connected to the evaluation unit ( 3 ).

12. A radiation source ( 1 ) which has a circuit unit ( 8 ) as claimed in claim 1 .

13. The radiation source ( 1 ) as claimed in claim 12 , which has a radiation-producing semiconductor unit ( 2 ), wherein the radiation-producing unit ( 2 ) is electrically conductively connected to the circuit unit ( 8 ).

14. The radiation source ( 1 ) as claimed in claim 12 or 13 , wherein

the circuit unit ( 8 ) is used to regulate a luminous flux in the radiation-producing semiconductor unit ( 2 ).

15. The radiation source ( 1 ) as claimed in claim 13 , wherein

the radiation-producing semiconductor unit ( 2 ) has at least one radiation-producing semiconductor body ( 7 ).

16. The radiation source ( 1 ) as claimed in claim 15 , wherein the radiation-producing semiconductor unit ( 2 ) has a series circuit comprising a plurality of semiconductor bodies ( 7 ).

17. The radiation source ( 1 ) as claimed in claim 12 , wherein

the radiation-producing semiconductor unit ( 2 ) contains at least one light-emitting diode or laser diode.

18. The radiation source ( 1 ) as claimed in claim 12 , wherein

the radiation source ( 1 ) is provided for the purpose of illumination.

19. The radiation source ( 1 ) as claimed in claim 12 , wherein

the radiation source ( 1 ) is provided for a headlight.

20. The radiation source ( 1 ) as claimed in claim 12 , wherein

the radiation source ( 1 ) is provided for the purpose of display backlighting.

21. A circuit unit ( 8 ) for a radiation-producing semiconductor unit ( 2 ), wherein

during operation a forward voltage U f is applied to the radiation-producing semiconductor unit ( 2 ) and the radiation-producing semiconductor unit ( 2 ) has a forward current I f flowing through it, wherein the circuit unit ( 8 ) regulates the forward current I f such that an actual value V act , which is dependent on the forward current I f and the forward voltage U f , assumes a prescribed setpoint value V set ; wherein the circuit unit ( 8 ) has an actuation unit ( 4 ) and an evaluation unit ( 3 ) and, wherein the actuation unit ( 4 ) comprises a voltage converter ( 21 ).

22. The circuit unit ( 8 ) as claimed in claim 21 ,

wherein the evaluation unit ( 3 ) comprises a nonreactive resistor ( 9 ).

23. The circuit unit ( 8 ) as claimed in claim 22 ,

wherein the forward current I f is ascertained using a voltage drop across the nonreactive resistor ( 9 ).

24. The circuit unit ( 8 ) as claimed in claim 22 ,

wherein the nonreactive resistor ( 9 ) is connected in series with the radiation-producing semiconductor unit ( 2 ).

25. The circuit unit ( 8 ) as claimed in claim 21 , wherein

the evaluation unit ( 3 ) comprises a mathematical circuit ( 10 ).

26. The circuit unit ( 8 ) as claimed in claim 21 , wherein

the actual value V act is a function f of the forward voltage U f and the forward current I f , wherein one of the following correlations applies: V act =f(U f *I f ); V act =f(U f /I f ); V act =f(U f +I f ); V act =f(U f −I f ).

27. The circuit unit ( 8 ) as claimed in claim 25 , wherein the actual value V act is ascertained using the mathematical circuit ( 10 ).

28. The circuit unit ( 8 ) as claimed in claim 21 , wherein

the forward current I f is a direct current.

29. The circuit unit ( 8 ) as claimed in claim 21 , wherein

the evaluation unit ( 3 ) has at least one first element ( 11 ) for determining the difference between V act and V set .

30. The circuit unit ( 8 ) as claimed in claim 21 ,

wherein the first element ( 11 ) is a subtractor which is used as a regulator.

31. The circuit unit ( 8 ) as claimed in claim 21 ,

wherein the actuation unit ( 4 ) is electrically conductively connected to the evaluation unit ( 3 ).