Patent ID: 6864867

Claim:
A drive circuit for an LED array including a first LED cluster ( 40 ) and at least one second LED cluster ( 42 ; 44 ), comprising: a switch (S 1 , S 2 , S 3 ) arranged in series with each of the first and second LED clusters ( 40 , 42 , 44 ), and each of the first and second LED clusters ( 40 , 42 , 44 ) having a supply terminal via which it is coupled to a supply voltage (U Batt ), wherein said switch (S 1 , S 2 , S 3 ) is adapted to be driven so as to permit a current flow in an LED cluster from among the first and second LED clusters that is associated therewith, a control loop ( 46 ) for driving the switch (S 1 ) of the first LED cluster ( 40 ) S 0 as to achieve a constant mean value of the current (I LED ) flowing through the first LED cluster ( 40 ), and the control loop ( 46 ) driving at least one switch (S 2 , S 3 ) of a second LED cluster ( 42 , 44 ), a total current detection device (R Mess ) for determining an actual magnitude (U Mess ) which corresponds to a sum of the currents through at least two of the second LED clusters ( 42 , 44 ), and a comparison unit ( 50 , 50 a ) for comparing the actual magnitude (U Mess ) with a prescribable desired magnitude (U OL ).