Energy supply for a light having a matrix of LEDs, in particular an LED motor vehicle headlight

A circuit arrangement for an LED motor vehicle headlight, comprising:

• an input for connection to a supply network;
• an adjustable voltage source, the adjustable voltage source having an input, an output, and a control connection, and the input of the adjustable voltage source being connected to the input of the circuit arrangement;
• a matrix of light-emitting diodes connected to the output of the adjustable voltage source;
• and
• a control unit to which the control connection of the adjustable voltage source is connected;
• wherein the circuit arrangement includes a plurality of series circuits, wherein each of the plurality of series circuits includes one of the light-emitting diodes and an adjustable current source through which a current through the corresponding series circuit can be adjusted;
• wherein each of the plurality of series circuits are connected in parallel with each other to form the matrix of light-emitting diodes;
• and
• wherein the adjustable voltage source is configured to adjust its output voltage to a setpoint voltage provided by the control unit at the control connection;
• wherein the control unit has an input:
• for reading in status information about temperatures in or at the matrix of light emitting diodes, wherein the temperatures assigned to individual ones of the light-emitting diodes of the matrix of light emitting diodes,
• for reading in measurement values of temperatures of individual ones of the light-emitting diodes of the matrix of light-emitting diodes,
• for reading in measurement values of a voltages across the adjustable current source of each of the plurality of series circuit,
• for reading in measurement values of a voltage across the matrix or across the light-emitting diode of each series circuit, or
• for reading in measurement values of a current through each of the plurality of series circuits;
• and
• wherein the control unit is configured to:
• determine the setpoint voltage from the read-in status information, from the read-in measurement values of a temperatures, from the read-in measurement values of a voltage, or from the measurement values of a current, which are provided at the control connection, so that the adjustable voltage source adjusts to the setpoint voltage,
• determine, for each light-emitting diode, a target current from the read-in status information, from the read-in measurement values of a temperature, from the read-in measurement values of a voltage, or from the measurement values of a current, so that each adjustable current source adjusts to the corresponding target current as determined by the control unit,
• determine a forward voltage for each light-emitting diode using the target current and a current-voltage characteristic curve for the respective light-emitting diode,
• determine a voltage across each adjustable current source using the target current and a current-voltage characteristic curve for the respective adjustable current source,
• determine, for each of the plurality of series circuits, a sum of the forward voltage of the corresponding light-emitting diode and the voltage across the corresponding adjustable current source, and
• select the largest sum among the plurality of series circuits as a modified setpoint voltage for the adjustable voltage source.