Driver circuit for illuminants (LED), especially LEDs, comprising: - a circuit , such as an inverter in the form of a half-bridge circuit, which can be supplied with a voltage (Vdc) and is clocked by means of at least one switch (FET1, FET2), - a resonant circuit , wherein the clocked circuit feeds the resonant circuit , - a transformer (L2) which follows the resonant circuit and starting from the secondary winding (L2b) of which the illuminants (LED) can be supplied, and - a control circuit (ST) which is arranged on the primary side (L2/1) and clocks the at least one switch (FET1, FET2) of the clocked circuit , wherein a measured value (ILED_PRIM) for the current is returned through the illuminants to the control circuit (ST), and wherein the control circuit (ST) is designed to clock the at least one switch (FET1, FET2) of the clocked circuit as a function of the measured value (ILED_PRIM) in order to regulate the current through the illuminants, characterized in that the driver circuit furthermore comprises: - a detection transformer (CTR1, CTR3; CTR1', CTR2', CTR3) having at least one detection winding (CTR1; CTR1', CTR2') connected on the secondary side (L2/2) of the transformer (L2) for inductively coupling an actual signal, wherein the actual signal indirectly represents the current through the illuminants (LED), and - an evaluation circuit which is designed to evaluate the inductively decoupled actual signal, to generate the evaluated actual signal as the measured value (ILED_PRIM) for the current through the illuminants (LED), and to return it to the control circuit (ST), wherein the control circuit (ST) is designed: - to detect, on the basis of the measured value (ILED_PRIM), an error state following the secondary winding (L2b) of the transformer (L2) and/or of the illuminants (LED) and to output an error signal as a function thereof. - a circuit , such as an inverter in the form of a half-bridge circuit, which can be supplied with a voltage (Vdc) and is clocked by means of at least one switch (FET1, FET2), - a resonant circuit , wherein the clocked circuit feeds the resonant circuit , - a transformer (L2) which follows the resonant circuit and starting from the secondary winding (L2b) of which the illuminants (LED) can be supplied, and - a control circuit (ST) which is arranged on the primary side (L2/1) and clocks the at least one switch (FET1, FET2) of the clocked circuit , - a detection transformer (CTR1, CTR3; CTR1', CTR2', CTR3) having at least one detection winding (CTR1; CTR1', CTR2') connected on the secondary side (L2/2) of the transformer (L2) for inductively coupling an actual signal, wherein the actual signal indirectly represents the current through the illuminants (LED), and - an evaluation circuit which is designed to evaluate the inductively decoupled actual signal, to generate the evaluated actual signal as the measured value (ILED_PRIM) for the current through the illuminants (LED), and to return it to the control circuit (ST), wherein the control circuit (ST) is designed: - to detect, on the basis of the measured value (ILED_PRIM), an error state following the secondary winding (L2b) of the transformer (L2) and/or of the illuminants (LED) and to output an error signal as a function thereof. <EOS>